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Tankless (On-Demand) Water Heaters

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Berkeley Parents Network > Reviews > House & Garden > Tankless (On-Demand) Water Heaters

Questions & Advice Related Pages

2011 - 2012 Questions

Tankless water heater install

March 2013

Hi, We are considering having a tankless water heater installed outdoors to replace our gas water heater. We'd be doing it as part of a bigger energy upgrade, and would be eligible for rebates. Reasons to do it include saving money, get more space in the kitchen where the water heater is, and I anticipate our current water heater is going to die soon. One concern is potential delayed hot water to the taps. I'm also surprised at how much it's going to cost- we were quoted $4300 for installation and removal of our old water heater. If you've done this, does this price seem reasonable? Were you happy you changed to a tankless water heater? Thanks! Big Bath Bills

The cost sounds reasonable. Tankless water heaters are expensive -- but well worth it, if you get the right one and have the work done properly. We had one installed for all of the reasons you list, and we love it. It's lovely not to have to worry about taking a shower when the washing machine is running (there's now plenty of hot water), our PG&E bill is way down, especially in the winter -- and we love the pantry we installed where the water heater used to be. The only times that the delay for hot water is noticeable is for the first person who showers in the morning (the master bath is the room that's farthest from the water heater), and when I wash dishes right after I get home from work in the evening. In both cases the water has to run for about 30-45 seconds. If the hot water has been running recently, there's enough warm water left over in the pipes to wash hands and such -- so it's not as much of a bother as I thought it might be. Karen
We got a tankless for the same reasons about 8-10 years ago and love it. Bought it and my husband installed it himself. It was a ton of work but he finished it and works great. If you have location options, install it closest to where you use hot water the most (kitchen or bathroom). We thought of putting in 2, one for each but decided to put in a hot water circulator instead. Husband installed again (he's handy) and it's a small door bell near the shower and kitchen sink. It sends the cold water in the hot water pipe back to the water heater and when hot, brings it back. So you push this little button and you can hear the faint noise of the pump pushing the water around. You get instant hot water. Good luck! tankless all the way
Rey Lacayo of Lacayo Colt Plumbing installed a tankless water heater at my house in Berkeley a few years back for much less than the quote you were given. I have been very happy with both the heater and the installation. We did not notice a real problem with the delay to the taps - the bigger delay is from the water traveling through the pipes, not the heater kicking on. Give Rey a call at 415-726-8549, he's a nice guy and I've had him do a few other plumbing jobs for us since then. Energy saver
Dear Folks- That quote is waaaay more than what I paid for my install. I am very happy with the energy savings, but I also needed to follow the 5-year rule...if the equipment doesn't pay for itself in 5 years it's not a good investment. May I suggest that you give Marius Construction a call? It's on the web and you also can refer to yelp! and other ratings sites for the work they do. First thing you need to do is get a price on the heater itself from a reputable dealer. Call'd be surprised at the differences. Marius always has me use Sincere Hardware in Oakland for just about everything. Call them and see if they carry tankless water heaters. Marius is always great about letting you order and pick up anything he installs. It saves him time and you money. The most important thing I need to mention is that you can TRUST Marius to be consistently fair and honest. It's real piece of mind. Give him a call and you won't regret it. suzymc
I just installed a tank-less after extensive research and waiting. I had 3 water heaters removed for various reasons and the best part was freeing up some valuable kitchen real estate. I spent about $5000.00 on the project. They need to put in new gas, electrical and other stuff. I had 8 bids and was shocked at how expensive it was which is why I took 4 months from PG & E shutting off the water heater to my master bath to make the decision! So far I have not noticed any appreciable difference on my PG&E bill. I may be saving in gas but it takes more electricity than the old ones. They take electricity to turn the water heater on and the traditional water heaters don't do that. Do your research, ask lots of questions and take your time making a decision. I went with a model that actually store 2 gallons so there is no delay in getting hot water which is usually a complaint. kelly
We replaced a tank water heater with an on-demand as a part of a large remodel, so I am not sure about the cost. It does take a while to get the water to warm up, but I am told there is an adapter that could boost this. We don't have the adapter and I sometimes think that what we save in heating the water we waste on running water to get it to heat up. I will look forward to your other replies. Best, Rita
You may not know about a third alternative to tankless and regular water heaters: Hybrid heaters that combine heat pump technology with a regular heater tank that saves about 60% of the energy with none of the drawbacks of tankless system: hot water delays and high installation costs. Basically, it installs almost like a regular heater, costs a little more up front, but saves a huge amount in energy in the long run. Here's a quote from Consumer Reports' Nov. 2012 online buying guide to water heaters (which included both regular and tankless models as well).

'These have a conventional electric storage heater paired with a heat pump that extracts heat from the surrounding air and uses it to help heat the water. Models we tested used about 60 percent less energy than standard electric heaters, which account for about half of all water heaters sold. And while hybrids cost more than electric-only models, installation is similar and payback time is short. But hybrids also have their downsides. Because the heat pump is usually on top, they need as much as 7 feet from floor to ceiling. You'll also need up to 1,000 cubic feet of uncooled space to capture enough heat from the air, along with a condensate pump (about $150) if there's no drain nearby. Hybrid heaters are noisier than conventional storage-tank heaters, exhaust cool air, and can rob some heated air in winter.'

Here's the overview:

Another article about hybrids:

This is from 2008, but CR found that tankless heaters were not necessarily economical:

My water heater is about 7 years old now and when it's time for a new one, I'm definitely getting a hybrid. When I replaced it last time, I switched from electric to gas, which also saved a lot of money. Becky

2009 - 2010 Questions

Experience with Instant Water Heater

Dec 2010

I'm really tired of washing in cold water because of how long it takes for our 'hot' water to really get hot. I don't even use the hot water tap because I don't want to waste so much water. I've heard of instant hot water heaters and would love to hear from anyone who has experience with one about their experience, and would also appreciate a recommendation on someone to install one. Looking forward to hot water Reva

In my brief experience with a tankless water heater it takes some time for the hot water to get to the tap, same as with tank heaters so just as much waste. I also had problems, which are common, with the temperature of the water varying, which is a real drag when you're in the shower. I got rid of mine! I deal with the waste while the tap water is heating up by capturing the water in a pitcher and using it to fill my dog's water bowl. If his bowl is full, I use it to flush the toilet, which we don't flush regularly for pee as a water saving measure. Cece
Not sure what you mean by instant hot water heaters, do you mean tankless? If so, you have to realize that if you are turning your 2nd (or 3rd) floor shower on, that there is still water (often cold) in the pipes leading to the shower and that whatever system you have, regular tank or tankless, the water that is already in the pipes (usually cold) will get to you first and that it will take some time before the hot water gets to you. Unless the tankless system is right next to the faucet, it will take a while for the hot water to get to the faucet. We had a tankless water heater installed a few years ago and they are good for continual/ongoing hot water (once the water to your faucet/shower head has gotten hot, i.e., the hot water has passed through the pipes and pushed out the cold water). However, if you want a lot of hot water (i.e., one or two showers are going on and the washing machine/dishwasher/etc.) is on, the tankless does not work as well. Having said all that, I don't think that a tankless will help with your instant hot water, unless it is NEXT TO your faucet. You still have to get the cold water out of the pipes first (yes, annoying, a waste of water, but true). MK
I know the moderator gave a link to advice on tankless heaters, but generally, those are also whole-house, so it will still take a while for the hot water to reach a faucet that is far away - and each time you stop the flow or slow it down, you have to wait again. A few thoughts (some just based on reading, some based on personal experience) - 1. Look at the piping from the water heater to the faucet. Ours was much longer/circuitous than it needed to be, adding to the wait for hot water (When we remodeled, we both moved the w.h. and re-routed some of the pipes). 2. If you are just talking about one faucet, there are small electric heaters that are truly instant - you install them right at the point of use, like under a sink. They heat only a small amount at a time, but that is what they are for. Much cheaper than whole-house tankless heaters, don't need to be vented out, but probably use a lot of electricity when in use. 3. Some folks put a circulating pump in the hot water system; it basically keeps the hot water moving around at a trickle all the time (or, in some cases, on a timer), so it's there when you want it. Obviously, it uses some electricity (not sure how much). One other downside is that some hot water ends up in the cold water pipes, so if you don't filter it for drinking, some of the stuff from the water heater is in your drinking water. 4. Even if you dn't do anything, you can collect the water in a bucket as you wait for it to get hot. We do this at the shower where it's a wait for hot water, and use the collected water to flush the toilet that's right by the tub. Some folks use it to water plants (if your yard needs water and it's not raining all the time, and you don't mind hauling a drippy bucket through the house!). R.K.

Tankless Water Heaters - have they improved?

Nov 2010

I was thinking of getting a tankless water heater, but the reviews on BPN are from 2008 or earlier and there seem to be a lot of complaints about them. Have newer models improved any? I'm looking to save energy and save space. Might want to mount the unit outside my house to save space. Don't like the idea of running out of hot water or waiting forever for hot water to reach me. I have a one story, 1500 Sq ft house. Also, any recs on makes/models/prices if I go this route? Thanks, BPN pals!

I just had a tankless system installed a week ago by Eric at Cal Plumbing (229-8022) and I am THRILLED with the results. (I also had my old galvanzied pipes replaced with copper.) Eric installed the Takagi TK3. Eric explained that not all houses are a good fit for tankless. But mine is a good fit being one story, not big (1000 sq feet) and only 1 bathroom. He also explained that the bay area is a very good environment for tankless because we don't have hard water that leaves deposits that need to be flushed out and that the incoming water is usually not colder than 50 degrees. Mine is installed in my basement but it could have been installed outside. Another reason to get a tankless water heater now is that there is a federal tax credit of up to $1500 for units installed in 2010. Eric is very experienced with installing these systems, was very easy to work with and on time. It usually takes only a couple of days and I wasn't without water overnight. thrilled with my tankless water heater
I had a problem with my new tankless, and found out - from a plumber friend - that the problems are usually due to a clogged filter. He cleaned the filter, and now it's good as new. So, keep your filter clean, and buy a good one to start off with. I LOVE MY TANKLESS! I'll never have another 'old fashioned' water heater again. (Takagi and Noritz are both really good brands.) Marilyn

Tankless water heater versus regular water heater

Sept 2010

I remember some discussions quite a while back on this site about the good vs bad of tankless water heaters, but I wonder whether there have upgrades on the technology, people's experiences etc. We have an older, 3000 sq ft house and we'd like to stop wasting water while heating it for showers. Any recent experiences or advice you'd like to share? anon

We have a tankless water heater - love it! The energy savings was significant for us.

That said, I will also tell you that ''on demand'' is not the same as ''instantaneous.'' Depending on the size of your home and where the unit is installed relative to your bathrooms, you still have to wait for hot water to cycle through the pipes.

Our solution to this problem was to install a recirculating pump on a timer that keeps hot water flowing through the pipes during peak shower times. During non-peak times, we just anticipate a wait for hot water. Hope this helps... Carolyn

I just had a tankless water heater installed in our one bedroom condo (ground floor). I got two bids from plumbers and they were almost the same, so I went with the one down the street. I really liked Albert Nahman's Plumbing, they were very professional and really helped me with getting the permit from the City of Berkeley after it was installed. One word of advice, it's worth having the professionals deal with the City, as they are used to all of the bureaucracy and crazy phone systems at the permitting department. They would have only charged for the permit and the time to get it, which for them was a couple of hours and for me was about 10 hours and one month worth of trying!!! Anyhoo, I got the Tagaki system and so far it is great. It fits in the bedroom closet, which is right next to the kitchen and about 15' from the bathroom. This opened up a huge space in my kitchen where the traditional heater stood. There is a slight delay in getting the water warm in the bathroom, maybe about 20 seconds, but I think the cost savings and SPACE savings are worth it!! Give Nahman's a call and they can talk to you about your own home needs. Carmen
About tankless water heaters: given that we have an older house and we were renovating only the kitchen, we were advised to continue using water direct from the traditional hot water heater that supplies the house.

Instead, we experimented with a Takagi gas-heated under counter tankless version. This required an upgrade to our gasline. While we did get instantaneous hot water, the supply would sometimes run out and we'd be back to cold water until the gas could heat the new tankful of water. The actual heater we used was a lemon and there would be periods of time when it would be under repair...extending for months in some cases because the warranty support was so poor. In the end result, even if it had worked as advertised, I'm not sure we would have ever gotten a positive return on investment. Also, I regretted the amount of space under the kitchen sink it stole from other purposes.

After 3 years of trying, we gave up and are much more content using a warm water circulating pump located at the hot water heater/tank. It is on a timer so that, during the hours we sleep, it is more energy efficient. These systems cost about $500 to $700 including installation. Grundfos sells complete packages under its Comfort System label. karen

I purchased a tankless water heaters and decided NOT to buy another after doing quite a bit of research. I found a university web site that performed an actual cost/benefits comparison of tankless over the lifetime of the heater. After 20 years they found tankless costs more and isn't any better for the environment than a traditional tank water heater. We've found our tankless uses more energy in the winter, and we wind up wasting more water. If power is lost, the tankless doesn't work at all. With a tank we always have hot water.

We have two houses. One hosue we have a tankless and in the other a 75 gallon tank heater. There are quite a few disadvantages with a tankless. We've found just about all of the claims on the benefits of tankless are false. The first disadvantage of a tankless heater is the cost it's 2 to 4 times more. Installation costs are much higher too. I was quoted $2,000 for tankless and $200-300 for a tank heater. Total cost to install a tankless was $3,800 vs. $1200 for a 75 gallon tank heater. We saved $2,600 by using a tank heater.

The one clear benefit of tankless is for the installer, they get to pocket several thousand dollars more off of each installation.

The next one I buy will be a tank heater. Anon

I was having trouble with my hot water pressure, and the plumber told me it was just the filter on my tankless. We cleaned it, and now have no problems. I LOVE MY TANKLESS - - it's a Noritz brand.
I recently researched tankless water heaters for a client. At first it looked like the tankless technology might be an option for her (she was replacing a 50 gallon conventional tank serving two older one bedroom cottages. However, on closer consideration we found that the flow requirements of the small cottages (each has one bathroom and laundry) would demand that we install a sizable heater at a sizable cost.

A plumber friend of mine has built a vacation home and he is using tankless, but he has two installed - one for the front half of the home and one for the master bathroom. He found that having only one small unit (which are now affordable) would not provide adequate flow if say laundry, dishwasher and shower were all run at the same time.

This does not mean that tankless is not an option, it just means that it must be sized properly. When I lived in Scotland we had a tankless heater installed to serve an attic bathroom and we were very pleased with the result. This was 20 years ago, so the technology is proven, even if it is not being used extensively in the U.S. as yet. Jim

Another option to tankless water heater is a water recirculater. There are two kinds; one that attaches at the faucet end, and one that mounts to the water tank (this is what we use). When the temperature at the faucet (the shower end) drops below a certain temperature water will recirculate from the tank. No water is wasted, it's nearly silent and it didn't seem to raise our gas bill by any noticeable amount. David
Changing from a tank style hot water heater to an instantaneous unit can be a good upgrade in that often one gains valuable real estate so as to be able to have more room in a laundry area.

However, more often than not, one needs to install a larger gas pipe as well as a larger flue to be able to allow the new unit to work properly. These units can be fickle if water pressure fluctuates or there is not enough gas that can flow through the pipe. These upgrades can be expensive and push the total cost past $3000 commonly.

What I've done at my house is to go to a higher efficiency unit, a 96% efficiency condensing unit - tank style water heater. The beauty of this unit is one can shave and have hot water to rinse off the razor - a pipe full of hot water rather than hot, a slug of cold, hot, etc.

The other great quality the unit has is that it can provide heat for the entire house via a radiant heating system or air handler that heats air for a forced air heating system. The latter unit is what I'm planning on installing in my house in the coming year.

Additionally, this type of system can be connected to a solar thermal system which could really drop one's carbon energy usage.

It is also a benefit to have 50 gallons of water on hand when the earthquake finally occurs and the water system fails. George

Tankless water heater versus regular water heater

Sept 2010

What are the pros and cons of tankless versus regular water heater? Albert

We have installed tankless heaters in two houses now, with very good results. One ah-hah moment that plumbers didn't mention to me was that while tankless heaters are twice as expensive as conventional, they last 2.5 times as long (plus the energy savings in the meanwhile). Buyers love them. East Bay Realtor

Debating whether to get a tankless or a standard water heater

June 2010

We are going to need to replace our hot water heater soon and are debating whether to get a tankless or a standard one. What are the benefits of tankless? Anyone went one way and wish they had gone the other? Any gotchas if we go the tankless route? Anon

We have a tankless water heater, and for the most part, I love it. No worries about running out of hot water after a LONG shower by my husband, no worries about sudden ice-cold if I turn on the hot water while he's showering (it gets slightly cooler for a moment, but not enough to upset him), lower gas usage overall (as seen on PG&E bill), and not so much worry about heavy metals sitting in the tank. Also we got ours put on under the house and are now able to use the closet it used to be in, as a pantry. Big bonus! The only real downside is the expected one: the first time you turn the hot water on after a long break (i.e. first thing in the morning or when arriving home from work), it takes a long time to get hot. And I do mean a long time. Also, the sink in the house that's farthest from the heater has the same problem all the time. I'd probably get one of those recirculators, or one of the instant under-sink heaters, installed just for this sink (the master bath) if I used it more. One caveat: be VERY careful with the brand you choose. We had to get our first one (a Bosch) replaced for various reasons. We now have a Takagi and it's much, much better. This is not a place to pick cheap. Karen
I almost went with a tankless water heater last month but decided against it due to the fact that I learned whenever you reduce the flow from your faucet or showerhead below 1/2 gallon per minute the tankless heater turns off and you end up with cold water instead of a reduced flow of hot water. I read about this and then confirmed it with a neighbor who has a tankless water heater. The 30% Federal tax credit makes tankless an appealing option but for those of us who do not run the faucet at full blast a shot of cold water sounded like an unreasonable side effect. FYI, I used Albert Nahman Plumbing (510.843.6904) as the company to install my new standard style hot water heater and found them very knowlegeable about tankless and standard water heaters since they sell and install both options. Reece
We got a tankless water heater about 5 years ago. Our gas bill dropped immediately. We're very happy with the flow rate and that we never run out of hot water. We can generally run two things at a time but they don't recommend three. Two problems: there is a delay to turn on the gas each time. This is to prevent wasting gas for short bursts. However, if you're washing dishes, the water goes cold. You have to get everything ready to go to rinse and keep the hot water on. The second problem was a maintenance issue recently. We live out in the burbs and the water here is bad. We got black flakes occasionally coming out in the bath water. Turns out that we were destroying the heating element. Recommend asking about a flush valve and have someone come out annually to maintain. May not be a problem if you get Hetch Hetchy water. Hot Water Lover
we have a tankless that was already in the house we purchased. we don't like it, mostly because every time we turn off the water while doing dishes (to conserve) and turn it back on again, it has to cycle back through and warm water up again. it will use what warm/hot water is in the pipes, but then it turns cold and warms back up. seems to waste water in our opinion. i like the space savings the tankless offers, but other than that i don't see the benefit. wish we had the old hot water heater
Hi -- We recently had to replace our conventional hot water heater, and we went with an Eternal Hybrid 'tankless' heater. It's similar to a tankless heater, but has a 2 gallon reserve tank that's always hot (not sure if other systems have that). My family of 5 has been using the heater for about 3 months now, and we're quite happy with it. I agree with the other posters that the availability of hot water is not quite as even as with a conventional hot water heater: we notice the water from the kitchen sink very occasionally (once every 2 or 3 weeks) gets cold (probably a problem with insufficient flow to activate the heater; neither we nor the plumber can figure out specifically why it happens, or, given that it happens at all, why it happens so rarely). We haven't had the heater long enough to say what it does to our energy bills. But really, occasional cool water seems like a fine compromise to make for using a system that doesn't waste spectacular amounts of energy maintaining 40 gallons of scalding hot water in our basement 24-7. Solar panels weren't an option for us (we just couldn't afford it), so this seemed like the next-most-responsible thing to do. Forgive the soap box there :). Good luck! Happy with my heater
I too was interested in a tankless, and I called Bart McCoy, a retired union plumber to look at the job. He is very versed on tankless and made sure I knew of all the pros and cons. After listening to him, I decided to go with a standard tank type water heater. He prebid this job for me and was a full $400.00 cheaper than 2 others I had talked to. You can reach Bart McCoy @ 510-289-1402 or 510- 350-7093. Good Luck, Erik

Cost to install a tankless water heater?

March 2010

Can anyone give a price range for how much it cost to install a tankless water heater? We currently have a regular water heater but would like to switch to tankless. Jennette

Eric at Cal Plumbing recently installed a tankless water heater at our house for $3400. The work included a seismic gas shutoff valve and some repiping under the house. With most tankless water heaters, you need a dedicated gas line from the meter, as well as new electrical wiring, so when you're getting quotes, make sure you're comparing apples to apples. Eric gave us a free estimate, and did everything to code and on time. His cell number is (510) 299-8022, and his office line is (510) 215-0200. Lovin' my tankless
Our water heater broke a couple of weeks ago when we had out-of-town visitors and were expecting more. Eric (Cal Plumbing, (510) 215-0200) arrived to give a quote on short notice on Friday night (we found him through BPN). He promised to have work finished by Sunday (he had already committed to a job on Saturday). He finished the job as promised and on budget, arranging to have an electrician complete his portion of the job on Sunday as well. Eric returned a couple of days later to install a seismic gas shutoff. Our visitors were amazed that we could get someone to do the job on a weekend. We highly recommend him. Kathy

Radiant Floor Heating & Tankless Water Heater

Feb 2010

We are going to lift our existing house and pour a new slab foundation in the new first floor. We would like to put in radient floor heating to heat the new bottom floor as we understand it is the most efficient way to heat a house. We also want to intall a new tankless water heater. How much does radient floor heating cost to install? Does it really keep the whole house warm (or at least the floor it is installed under? How much can I expect to pay to install a tankless water heater? Can it really heat up water enough for two showers, laundry and dishwashing at the same time? Is there a bigger capacity system that I should look at? Just wondering

Yes and Yes! We have radiant floor and tank less heater in our 2 level home. The floors are warm and the entire house feels as though it has been warmed by the sun. No forced air, no noise, no weird smells, just cozy warmth!

As far as running 2 showers and your appliances- yes- you will get enough hot water but your water pressure will be low. Be sure to talk with whoever will install your system about water pressure.

We installed our radiant heat and tank ourselves so I am no help as to cost. DIY

Not sure I can address all of your questions, but here goes: I agree that radiant heating is efficient and it is the most comfortable heat. With a new slab floor on grade, I always recommend pouring a topping slab with the radiant tubing in it. This allows you to separate your heated slab from the structural slab with some thin layer of insulation (bubble wrap often used).

Now, the heating system and the water heating system are not always combined. This gets technical, and you will want to know the differences.

Tankless water heating systems take some getting used to, and sometimes have to fiddled with over time to get the optimal results with the units you decide on.

Yes, these systems keep the whole house warm. You can heat the upstairs with the same system in various ways (one way is with radiators).

Costs vary, and I would not venture a range without knowing more about your specific requirements. AB

2007 - 2008 Questions

Sept 2008

Seeking some detailed advice on Tankless Water Heater with possible added use for radiant heating We are planning a kitchen remodel with possible replacement of our current tank type heater with a tankless model which seem to be all the rage. As the only heat source in our 1600 sq. ft. home is an antique living room floor furnace, we are considering a large capacity tankless water heater for both domestic hot water AND radiant heating (either under-floor retrofit or baseboard radiators). Have any BPNer's installed such a system ... and if so, who did it and how did it work? We would also like any very specific advice on tankless water heater installations ... especially folks willing to provide specifics on the installation ... ie make & model, location of heater relative to points of use, flow rate needed to ''start up'' the heater, installation & maintenance issues, decrease in energy use? INCREASE in water waste? etc. etc. etc. Linda B.

I've been installing and maintaining water heaters for quite some time now and experience and research has lead me to the conclusion that tankless heaters are not the bargain that they are touted as.

A tankless system's initial cost plus the often higher installation costs usually save little or no money over the average life of the unit. I can maintain and repair tankless units but they usually last between 8 and twelve years before they need to be replaced. This often happens around the time that you begin recouping your original investment. A normal tanked water heater can last indefinitely when given the correct and timely maintenance, especially with the water quality we have in the Bay Area. They are simpler to repair ( I can show almost any homeowner how to do this), the parts are much easier to maintain, and they don't have all these sometimes bizarre problems that accompany the tankless units. Radiant systems are another matter, I can send you a good article about them that may help you familiarize yourself with the subject. Good luck! It's often a very 'tankless' task.....groan

We are a small plumbing company that specializes in radiant heat. We also install lots of tankless water heaters, although never as a heat source for the radiant system.

A properly designed heating system will have a difference in temperature of 10 to 20 degrees. This means the supply water (water leaving the heat source) is 10 to 20 degrees hotter then the return water (water coming back to the heat source).

Tankless water heater numbers. A tankless water heater is designed around a 40 to 80 degree difference in water temperature. 55-degree ground water to 120-degree output temperature is the most common rise in water temperature that a tankless water heater sees.

This means that to meet the temperature difference in a radiant system the water heater will be flashing on and off. This shortens the life of a tankless water heater and combined with the 15 degree difference in water temperature changes the efficiency of the water heater down into the 75% range. This short cycling does not allow for the proper flow of flue gases from the water heater, which leaves behind deposits on the heat exchanger, further reducing the efficiency of the water heater over time.

After reading this you may wonder why people use tankless water heaters at all. Well, for domestic water heating they work great. Tankless water heaters can also be used in low temperature heating of 140 degrees or less when used in conjunction with a properly designed tank loading system that allows the water heater to be operated with a minimum temperature rise of 40 degrees.

Yes, you can design a heating system with a 40-degree drop across the system to make the tankless water heater work at the bottom of its proper operating parameters. A 40-degree drop in water temperature requires a large heating load. 80% of the time we have small heating loads. The reality is that you are far better off using a boiler to heat your house. The boiler's primary purpose is to heat with greater efficiency, last longer and have a better warranty.

The boilers we install are Triangle Tube modulating/condensing boilers that carry a 95 percent efficiency rating and come with a five year parts AND labor warranty, with an extended 10 year parts and labor warranty available. They are considered by many to be the best on the market. Jeff

A few years ago I installed both a takagi tankless with a small radiant loop for my cottage and a new sears 50 gallon gas water heater with 4 loops for my house. Both are ''open'' systems so they provide both hot water for showers and hot water for heating. This type of system has to be designed so that when you take a shower, fresh water enters the floor loops so that they don't end up with stale water growing stuff over time.

I mainly used the tankless in the cottage since it took up a lot less space than a regular water heater. Takagi are computer controlled so I find that mine heats the floor without cycling on and off, it just runs the fans and burner much lower than when I am taking a shower. It's entirely possible that it's running at less than peak efficiency and while mine has been trouble free they are expensive to fix if anything goes wrong.

For the house I chose to get a regular sears 12 year 50 gal water heater since at $500 it is so much cheaper than a boiler or tankless there's no way the extra efficiency would be worth the cost over the lifetime of the unit. I think the boilers make a lot of sense if you live someplace cold or have a large house. For small and medium Berkeley houses the total system cost seems unjustified. I ended up very happy with both of mine and wouldn't change them. Alex.

May 2008

I'm interested in hearing good and bad experiences with tankless water heaters (specifically in a remodel) now that they have been out longer. The archives have not been updated in over a year. suzie

We went tankless when we remodeled and we would totally recommend it! Because it heats water only on demand, it's FAR more efficient than a standard water heater, which means your bills should be lower. You can mount the unit outside so it frees up space inside your home. It definitely seems like the ''green'' choice since it only heats water when you actually need it. The water heater itself lasts much longer than a standard boiler. And if you're a fan of a long shower, it will heat water *continuously* as long as you want. The only downside, which we find quite minor, is that it does take a minute or two for the hot water to hit the faucet, and it does feel wasteful running the water waiting for it to heat up. I think there are under- sink units, basically miniature water heaters, that you can install to serve up hot water immediately while the tankless gets heating, but we haven't really looked into that yet. Loving Tankless Water Heater
I am not sure what sort of advice you are looking for on this one...but, we had a tankless water-heater when we lived in Europe from '99 through '02 and loved it. We never had a problem with water getting cold that I remember. When my niece came to visit we were able to lock in a temperature on the tub spigot that she couldn't accidentally 'hit' while playing and subsequently get sprayed with scalding water. Apparently, they have been around FOREVER (fifty years or so) elsewhere in the world, but are just now making their way to this side of the pond... jan
To solve the problem of waiting minutes for hot water, we installed a re-circulator with a timer on it. The timer allows you to set the time for when you want hot water immediately, and it has an off/on option for those times when you want manual control. We set the timer for the 1.5 hours in the morning that we normally shower. When we need to use hot water outside the morning shower period, we flip the switch on, then flip it off when we are done. We turn it off completely when we are away on vacation, or on weekends when our schedules are very different. This has made the system truly efficient for us. Cathy
Feb 2007

Does anyone have information on tankless water heaters. I need a new water heater and was thinking of getting one. I know they are more expensive than regular water heaters to purchase and install, but I understand my heating bills will be less. If you have one, do you think they are better? Diane

We have a tankless water heater. I don't know how much it cost as the house was already equipped with it when we moved in. However, I can speak to the pros/cons of having one. Overall, we're pretty happy with it. Never having to worry about running out of hot water, easy temperature adjustment so in the summer time when its hot out, you can turn the heater down so the water is only mildly warm. We only had one issue once where the unit malfunctioned and once we called the manufacturer to figure out why, we were able to fix the problem ourselves. The only real downside is when the power goes off (which happens kinda frequently when there are bad storms) you have no hot water AT ALL. Literally as soon as the power goes off the water turns ice cold. At least with a hot water tank you have some water already heated so you have a reserve. If you don't experience alot of power outages, then the heater is probably the way to go. If you do, then you might want to think twice. Lisa W
I had a Takagi tankless water heater installed as part of a remodel three year ago and have been very happy with it. It provides endless hot water even if you have shower, dishwasher, and washing machine going at once--or back-to-back showers or baths for everyone. The only drawbacks are that it takes a while to get hot water in the sink furthest from the heater (though it did when I had a tank as well), and it's a bit noisy when it's running. I had the tank installed outside so I don't hear it much but I notice it when I'm outside. Also if the electricity goes out it doesn't ignite even though it heats with gas. It's way less expensive for the gas and you know you're not heating water when you're not around. Happy with my Heater
When our water heater went out last fall, we also wanted to get a tankless heater. But after several days with no hot water, here is what we discovered: tankless is generally preferable for new construction where you can control the configuration, but almost nobody puts them in existing construction because of the expense of the venting. The heater itself is not that expensive - obviously more than a normal one, but would pay for itself in energy savings in about 5 years. The problem is that tankless heaters produce NOx emmissions, so you have to get special, very expensive (cat 1?) venting installed, and the vent outlet cannot be within 4 feet of a door or window, or under a deck. Give those constraints, we would have had to vent through the roof. That would have cost an extra $1000, on top of the cost of the heater, because our heater is all the way down in the basement. With that cost, the heater would have paid for itself over about 10 years if you calculate without interest. Since 10 years was the total life of the heater, it wasn't worth it. went standard
The tankless waterheater industry will certainly tell you the bills will be less and theoretically it makes sense that they would be (the water is only being heated as it is demanded instead of it being continually heated on reserve). However, we went tankless for our 3 unit building (Takagi T-M1) about 5 months ago and I can't say that our energy bills have declined very much. I think this is in part because there tends to be a surge of cold, followed by warm water than 15 - 20 second later a slug of cold water passes through the pipes. Thus, we (and our tenants) tend to let the shower run 30 - 60 seconds seconds before getting in which uses electricity AND more water than we'd otherwise use.

That being said, the space savings is huge, and with the $300 tax CREDIT available on many of the smaller single-family residence units, going tankless really isn't that expensive. From my research Takagi is the best and most reliable. Also, be sure to have a professional plumber install your unit or the warranty will be void. Chad

When we remodeled our kitchen we replaced our conventional WH with a tankless. It handles kitchen sink, dishwasher, washing machine and one bathroom (used regularly by one person.) It is a Rinnai Continuum. (We have a separate WH for our main bathroom, but I plan to replace it with a tankless one of these days). Mostly I have been really pleased by it. We've never run out of hot water and the extra space made available when we got rid of the old water heater was delightful. Should have done it years ago.

The downside: our model, and most likely all the others, doesn't allow you to run a small stream of hot water. If you turn hot water to a trickle it comes out cold, so water conservation is difficult when handwashing dishes. Also, make sure you get the proper thermostat for your application. We accidentally picked up the ''bathroom'' rated thermostat, which maxes out at 120 degrees. Fine for most uses, but I would prefer the option to raise it to 140 occasionally, which, I think, is the max for the ''kitchen'' rated thermostat.

And another caveat: for whatever reason, it seems to take a little longer for the hot water to reach the faucet, so we positioned it just several feet from the kitchen sink (the water we use most regularly). Lisa

2005 - 2006 Questions

May 2006

I've looked at the reviews in the archives for tankless hot water heaters and most are negative. I'm looking for positive reviews, from people happy with their heaters. And if so, what is your secret, since most people seem to be unhappy with these things (one person mentioned adding a recirculator, is this the key to hot water heater happiness?). I had hoped getting one would be my salvation, and my key to an endless shower, but I'm a bit deterred by the negative comments about how long it takes for the water to get hot and the logistics when turning the water off or down and then back on. Thanks. Amy

In response to the person looking for good feedback on a tankless water heater, we totally love ours. Sure you need to wait a little for the hot water to arrive, as some people complain. But, it's hardly a big deal (yes, it's a waste of water, but you save a huge amount of energy, which is immediately noticable on your first pg and e bill). It costs a bundle (we used albert nahman for installation due to good reviews, though high price), but pays for itself in around 7 years. Totally recommend it, not only because it's a better environmental choice, but also because we can actually take a bath without running out of hot water. Jamie
we love our rinnai. i don't find that hot water takes longer to arrive at a faucet. sometimes the hot water doesn't want to come (the heater not switching on after turning water on and off) and i just turn the faucet to cold, and then slowly move it to hot. the last time this happened was weeks, if not months, ago. we also love that there is an internal temperature control - so when my daughter is in the bath i turn it down and there is zero risk of hot water burn. its also fun to have hot water available outside the house for her little pool, we just hook up the hose. we have no issue running the washing machine, dishwasher, shower and kitchen sink at the same time.

i think our contractor used lundt merrimore as the plumber. i asked for the biggest bad-ass model available. as a water heater - it is slightly more expensive. BUT - all the new plumbing to the outside, and then fixing up where the old tank was, cost some big cash dollar bills. Julia

we are happy tankless water heater users. We have a tk2 and switched in January from a tank. We saw a 2% reduction in gas use despite high furnace usage in winter months. This past month we had a 50% drop in gas usage w/ very little furnace usage from the same month in previous year. You do wait a bit for hot water. However, we had that problem from pipes being distant from water heater before, so it's not that different. We have made some changes in our 'style' of usage. We heat hubby's shaving water in a mug in the micro wave to get a hot dip after cold rinsing the razor, so as not to constantly retrigger the heater after turning it off. And we might tend to leave the h20 running in the kitchen sink or fill a dish tub w/ hot h20 to avoid the same problem when scrubbing pots, depending on the size of the job. OUr h20 usage has not increased notably. It's great to fill a bath, and to be able to add piping hot water in several seconds over the course of a long soak. We can ! run an appliance and still have hot enough water at the sink or shower. happy and tankless
When we built our new home last year we put in two tankless hot water heaters. Our home is two story and the heaters are in the attic space. One heater services the kitchen (sink and dishwasher), the master bath (two sinks, two shower heads) and the clothes washer. The other heater services the 1/2 bath on the first floor and two other bathrooms (both w/ one sink and one shower). We have never had any problems with the amount of hot water needed and we've had lots of "water events" happening at one time. As for the time it takes, heck I've lived in homes w/ the regular hot water heater in the garage where it takes five minutes to get hot water to the master bath on the other side of the house, so waiting just a min or two is no big thing. The only room where it matters is the 1/2 bath on the first floor. Since one really just washes hands in there, the minute feels very long. We probably should have put a small flash heater right in that room.

We LOVE our tankless heaters - everyone can take long showers and there's always plenty of hot water to go around. Feel free to email me if you'd like to know specifically what kind we have and how big they are. I don't remember, but my husband knows all that stuff. Robin

May 2005

About 2 years ago, we had a tankless hot water heater installed (an apparently fancy, Takagi TK2), and I'm fairly disappointed--wondering if my expectations were too high.

It takes 30+ seconds to get hot water in our kitchen and 60+ seconds to get it to the bathroom sink, ~6 and 20 feet from the heater respectively. Also, if I've got hot water running in the kitchen and I reduce the flow but don't change the temperature, the water goes cold and I have to crank the flow back up and wait again to get the not water back. Needless to say, we're wasting lots of water waiting for it to turn hot.

I had our plumber come back to ask if this was normal, and he advised that we had sort of large pipes (which they had installed 3 years prior) so it would take a while for the hot water to flow (of course we weren't advised of this when they sold us the expensive hot water heater) but didn't have a good explanation for the other stuff, and proposed a $500+ tiny water tank to keep some hot water on reserve--seems to defeat the purpose. I can't believe that this is how the product was supposed to work.

Does anyone out there have this same hot water heater and experience or (please!) does this some malfunction/ adjustment problem? It infuriates me every time I turn the water on. feeling wasteful and shnookered

We also have a Takagi TK2 tankless water heater and experience each and every symptom you describe. And my husband is a plumber and wanted this system and installed it himself and told me that is just the way it is going to be. For us, we moved the water heater farther away from the old one so that we could install it on the outside of our home, so this seemed to explain the delay in receiving hot water. I mainly have a problem in my kitchen and not so much our bathroom. But I do not like that when I wash dishes I have to keep the flow of water higher just to keep hot water going. His solution is also the same, a small water heater under the sink to start the supply of hot water while you wait for the tankless to kick in. though it still seems worth it in the end. you are not alone
We have a TK2 also, installed with our existing old pipes, and it takes about 5 seconds for us to get hot water in the bathroom that is about 6'away, and about 30 seconds to get it to the kitchen, which is about 15 feet away. I also agree that the kitchen thing is a drag - when you wash dishes by hand, it's hard to get the water to: A) hit a medium hot stage and stay there, and B) not go cold again between rinses [because you don't want to keep the hot water running...].

I think I could resolve 'A' if I install a kitchen faucet with seperate hot and cold controls, like in the bathroom, where I have no problems with it, instead of the one single handle kitchen type we use now. Jean

My husband and I recently purchased a tankless water heater as well. We also have the problem you mention with long wait times for hot water. Our problem is sporadic, though, with wait times up to 10 minutes in the bathroom sink! It's totally unacceptable and does defeat the purpose of purchasing a tankless solution.

I'm sorry that I don't have any advice to offer, only empathy! I'm going to contact a plumber, though to look into our situation and will report anything I find out. I do suspect that it's a problem with our pipes, though, as we also have a flow issue and old pipes. Good luck! Mary

We also have a Takagi and have the same problem with slow warm-up. It's typical of tankless heaters. I know of two ways to solve the problem: 1. you can buy a booster mini heater that fits under your sink ... they are relatively inexpensive, and though I had information about where to buy them a while back I've since misplaced it. 2. You can take the low-flow filter off the faucet and let the water run more freely. This doesn't save water, but it does speed up the process of getting warm water to you. When I'm in the bathroom I just turn on the bath and it's warm in a few seconds; with the sink and its filter it takes about two minutes. Jodi
I had some problems with my Takagi T-K2 also, but mostly because my pipes were too small, and you say that you were told that yours are too large! I do not believe that there is such a things as pipes that are too large for this heater- the installation manual gives instructions for up to at least 1 1/2", and I really doubt if yours are bigger than that.

I spoke with the tech department at Takagi (the main number is in your manual and they have a local branch in Fremont), and verified that my 1/2" pipes were too small. This was causing pressure loss, and temperature flucuations.

I had a problem that sounds like yours with the disappearing hot water, and that turned out to be because the switches on the inside of the unit were not set properly- there are different settings for indoor and outdoor installations, and for different basic temperature settings. All of that is in the manual also.

I also had to wait for what seemed like a long time the hot water also, which drove me crazy. I started keeping a pitcher by the sink so that I could save the water for other purposes rather than wasting it.

I used a basic plumber for the installation of mine, and he was way over his head when it came to problemsolving. I figured most of this out myself by talking with Takagi. If I were to do it again, I would have it installed by someone trained by Takagi.

You can have a tech person from the Fremont branch come out and do a conultation, probably a good idea! Cecelia

We installed a Noritz brand tankless recently and had the same issue as a previous poster - the need to run the water a while b/f it got hot. We then had a recirculator installed and this solved the problem. We live in a large ranch style house, and at any of the faucets, we now get hot water in under 3 seconds. We have the recirculator on a timer so that it does not run when we don't need it. By the way, our gas usage is about 1/2 of what it had been! Cathy
With respect to the posts regarding a delay in receiving hot water at your faucet or shower, I believe this is inherent in all on-demand waterheaters. For one, on-demand water heaters require a minimum demand flowrate before they turn on and begin to heat the water passing thru the unit. In general, the minimum flowrate is about 0.75 gpm. With household faucets having about 1.5 gpm max (at about 50psi water pressure), a slightly open faucet may not demand enough hot water to start the system, especially if the faucet is not set to full hot. Also, the cold water in the line must be cleared first before the heated water can reach the faucet. Unlike a regular waterheater which fills the line with heated water at all times, the on-demand only generates hot water in the line when turned on. When sufficient demand is not present to turn the unit on, cold water will be passed thru the system. Okii (Sept 2005)
The problems these ladies describe is typical of tankless water heaters, both the on-demand units these ladies have and same for the tankless units in a furnace. Even though they are rated for 6 gal/min, we don't know at what temperature the water will be delivered and how long is the recovery time. The problems with on-demand units are the main reason people still use a tank water heater. If you run water slower, the problem may be less. This is because it takes time for the heating medium to transfer the heat to the passing water. The speed of the passing water affects the amount of heat the water can pick up. Also, the fire may have been extinguished due to water being hot enough at the moment and would have to start up and start heating again. Another solution (admittedly expensive) is to install an on-demand unit at each point of use. Berge (Feb 2007)
March 2005

I've scanned the various comments on tankless water heaters and I'd like to know if anyone has more to add. I'm considering a tankless whole house unit for a 3.5 bathroom home with 3 adults and two kids (one a teenager). I've looked at the various units available and it seems like either a Takagi TK-2 or TM-1, or a Noritz N-084M, is appropriate for the size of house and potential peak demand (maybe). All require a 3/4'' gas connection (my current water heater only requires a 1/2 inch connection) that will need to be installed. Has anyone had experience with these units (positive or negative). In real world conditions, have they provided sufficient hot water for two or three simultaneous showers? Any drawbacks to these units besides the upfront costs (maintenance?)? I believe that all require AC to run, so I guess during power outages you have no hot water, right? Thanks okii

Just to let you know (Okii and anyone else who might be interested) I have a new Takagi K-2 tankless hot water heater that my plumber mistakenly recommended for installation on a 1/2" water line, and as Okii points out, it needs a 3/4" line.

Takagi's are top of the line, and generally last about 30 years, as opposed to 10-15 years for a regular water heater. It is out of the box and was installed for 2 weeks, so I can't return it, and I need to sell it and recoup my money. I will sell it at a good discount off list price.

I have checked with Takagi, and there is no risk to the unit that it was installed (for 2 weeks) on the wrong size line. The problem is only that it didn't function consistently on 1/2".

I have the outside vent cap and remote control panel to go with it, and possibly some of the plumbing and gas fittings that I won't be needing. Sadly, I've had to go back to a plain old-fashion water heater.

Please contact me if you are interested. Cecelia

Jan 2005

I'm interested in advice on replacing a traditional water heater with an on-demand heater. Can it be done without remodelling? Are there plumbers/other tradespeople who specialize in this? My house is a one-story craftsman's cottage house with one bathroom. carol

We checked this out. We didn't speak to a specialist, but all the companies we spoke to (big plumbing companies in Berkeley and water heater-only places) seemed knowledgable.

The bottom line is that they are much more expensive than standard water heaters and are popular in Europe only because European houses don't have space for standard water heaters. A large-enough regular modern water heater is supposed to be able to supply all your hot water needs.

Regarding remodeling: I was told that on-demand water heaters require copper plumbing and the gas exhaust flue has to be large enough to handle the BPU's of the water heater. But different companies said different things. Best wishes for getting the true and complete story! I recommend that you find a place that has a lot of experience installing them, which it sounds like you are trying to do anyway. Sorry I can't give you a recommendation. Francesca

We replaced our traditional water heater with an on-demand heater about six months ago. It was done without remodeling q we got an exterior model (Rinnai) and had it placed on the back of our house. Itms pretty small, isnmt eye-grabbing. We hired Nahman Plumbing. They were great. Wemd use them again. Tell them Shirley sent you! Shirley
RE:on demand water heaters My husband recently installed a Takagi TK2 on demand water heater and we love it. Never run out of hot water, lower gas bill, and more space in our downstairs basement room because we installed ours outside. He is a plumber so when our water heater needed to be replace that was all he wanted to replace it with, nothing else. It is more expensive than your traditional water heater but well worth the investment into your home. You can call Mr. Rooter plumbing and ask to talk with Spencer Ferguson if you would like more advice than I can give you. 510-843-6378

2004 and Earlier

Sept-Oct 2004

Hello, we are looking into replacing our conventional water heater by a tankless water heating system. We want to run several appliances concurrently (bath, shower, dishwasher) if needed, and have a two story house. There are many systems out there, both gas and electrical ones, and they seem difficult to compare. Does anyone have good experiences with a particular brand, and sees any advantage of using electrical over gas types? Thanks for your advice to the novice! beatrice

I am interested in having a tankless hot water heater installed in my very small (under 1000 sf) house. I am interested in hearing which brands are best, where to buy them, where to install them inside of the house, and who can install them quickly, honestly and economically. I am very eager for feedback. Thanks. Rebs
We just installed a Takagi TK-2 and its great (it cut our gas bills in half). People I've spoken with say Takagi is the best; my advice is to go for a larger one like the TK-2 (they're all small anyway) if you plan to do anything simultaneously (shower and dishwasher) Sheridan
We have a tankless water heater and love it - my husband is a contractor so we installed it ourselves and have had no trouble with it at all. The brand is Aqua Star. The only thing is for a bigger household is that you couldn't take two hot showers at the same time, but otherwise it is great. Cassi
Feb 2004

My wife and I are considering a tankless water heater -- i.e., a water heater that heats the water to be used on demand rather than always heating a full tank. The idea seems good to us from an environmental and economic standpoint. There are some older postings on this subject, but I wanted to hear about people's current experience and advice -- can these heaters service a 3 bed/2 bath house with kids, dish and clothes washer, etc.? If so, any recommended brands, retailers, and installers? [PS: we were originally thinking of going solar, but a couple of folks recommended against it -- should we keep looking at solar for water heating or is that a thing of the past?] Thanks!

My husband installed an on-demand hot water heater 2years ago (a TK1). We have an 1100 sq' house, 2 kids, a dishwasher, & we wash diapers in hot water. I have tried washing a hot washer load while taking a shower, and while the temp dips a little, it was not a problem for shower- taking, at least. It is heavenly for back to back showers. Check the Takagi website to see what might be adequate for your uses. There are a couple of downsides to on-demand: 1) It is a gas unit, but electricity powers the computer and blower fan. If the power goes out, (picture mid- shower) the water runs cold. Instantly. My husband installed a UPS backup power supply to take care of this. 2) In a regular hot water heater, when you turn on the hot water, you get the cold water in the line first before the hot starts coming out. Once you do this, you get hot water from the tank, even if you turn it off and on over a period of time. With an on-demand heater, you get the cold water at first, then hot. BUT, every time you turn it off and on again, even after only a few seconds, you get COLD again, and have to let the water run again. This is because it takes a while for the burner to heat the water up. So, you end up wasting tons of water if you are using it intermittently. This is a major drawback. It is possible that the newer heaters have addressed this, we don't know. Otherwise, it might be advisable to look into a circulating pump system if that would work with the heater in question. 3)My husband discovered that it required a large size gas line, and had to replumb sections of our older house. 4) Cost. We bought a scratched/dented version from CET Solar on line, and it was still $750 (2 years ago), more than twice the price of regular hot water heaters. They've come down a bit, but still pricey. We will be moving soon, and would set up a on-demand heater again, but only with a recirculating system in place. janet
In response to the guy thinking about a new waterheater, I just did a bunch of research on the tankless ones -- Takagis and another comparable Japanese brand. The result of all this is that we still don't know what we're going to do. The tankless heaters CAN apparently deal with a house your size no problem, but they cost a lot more up front (about $900-1000) and a lot more to install. We found that to buy and install a conventional heater would cost us about $1000, and to buy and install a Takagi would cost AT LEAST $2600, if not more. It'll take a long time (like over a decade) to recoup $1600 from the savings in our energy bill, and so we are not sure it'd be worth it. Wendy
A few more thoughts on the tankless hot water heater issue: We recently did a kitchen remodel, and as part of that whole project, we got a tankless heater. We did it primarily because we were able to put it outside, on the side of the house. It is only about the size of a suitcase. The problem was that, as part of the remodel, we needed the space that had formerly been used as the vent shaft for the furnace and hot water heater. We had already had to replace the furnace, and the new one vented out of the side of the house. By switching to a tankless hot water heater, we were able to eliminate the vent shaft entirely. Also, we now have room in the basement where the hot water heater used to be for more storage. On the downside, the unit was quite expensive (about $900), and it was also expensive to install (about $500) (also we think our plumber tried to rip us off, but that is another story). It also, as others have noted, requires you to run the water for a few minutes before the hot water flows. We did not realize this. We thought we were doing a great thing getting an energy efficient heater, but now I worry about wasting water. Anon
June 2002

Our water heater needs to be replaced pronto and we want to get a tankless model that heats on demand, like the Aqua star. We will likely try to install it ourselves. There are several other brands that I've heard of. Does anyone have any advice for us regarding brand and model or installation? How about where to get one for a good price? I know that Real Goods carries the Aqua star. We have one bathroom, a front loading washer and a dishwasher. We do sometimes use more than one thing at a time and may add a bath in the future. Thanks so much, Natalie

I don't think an Aquastar will do it for you. I would try Takagi or Paloma. We just installed our own Takagi. It's great. We can run two things at once, and we have endless hot water. I don't think the Aquastar will let you run 2 appliances at once. You should check the FLOW RATE for the different models. Check on line to for info. and get to know the product.

Our neighbor has an Aquastar-- and it only runs one appliance at a time. Ours cost more-- around $1000, but it's worth it (should take about 3 years to pay off the extra expense with energy savings) The install went ok- - but you really need to be handy with plumbing and electrical, AND you need a 3/4'' supply line for the water. Now that ours is installed-- we love it. Getting it up, and getting a new supply line in took time and patience. Angela

We bought an AquaStar water heater last summer and had it installed by our contractor during a remodel. We ordered it on the web from CET because they had the best price. Even with shipping we saved at least $100 over what Real Goods charged. Unfortunately it was defective, so we had to return it. The replacement has worked fine. We bought the medium-sized model, and find it gives us more than enough hot water, especially since we replaced our plumbing and no longer have ancient pipes full of crud. The trick with these heaters is that they only go on when you have enough water flowing, and, as with any water heater, you have to wait for the hot water to reach your end of the pipe. The extra large size requires a higher flow rate and we thought we'd waste water keeping the hot water coming. Don't know if that's true, but we seem to have picked the right size for us. It isn't an energy star, but it's nice to have a small heater on the wall above the washer instead of an ugly tank wrapped in insulation. Robbie
Feb 2002

A while back there was some discussion of on-demand hot water heaters. A few months ago we installed a new one. After doing some research we chose the Takagi TK-1 over the Aquastar. It is a bit more expensive and less readily available, but has a higher flow rate. It's been 4 months now and we love it. It provides enough hot water that we can run several things simultaneously- we no longer have to turn off the dishwasher when someone is taking a shower. We never notice a lack of hot water anymore. We did have it installed by our plumber, who purchased it at Cal Steam in Emeryville. (Now does anyone know what to do with an 85 year old, cast iron on-demand hot water heater? We've been told it may be worth some money...) Gayle


My "tweens" have driven me to a search for a better water heater. We have increasingly pricey natural gas. Has anybody tried the flash type water heaters? Where would I get one and how would I get it installed? What is the best kind? We are a household of 5

The type of water heaters that you are talking about use large amounts of electricity. Here's a web site that offers this type of water heater:
We got an ELM Aquastar water heater about seven years ago. It works like a car radiator in reverse. When you turn on the hot water, it makes a charming "Whoosh!" as the gas burner turns on and starts toasting dozens of fine tubules.

No question, it's efficient, and we've never run out of hot water. It takes up less space than a tank water heater and is easier to clean. Downsides: it can't be installed in a confined space such as a closet, and requires a wider exhaust pipe than a tank water heater (so a bigger hole has to be made in ceiling and roof). The temperature of the water from ours creeps up every few months, requiring adjustment. We've heard that bits of grit in water can clog up the heater's many fine tubes.

Finally, it needs reasonable throughput or it shuts off. As a result of this and our house's poor water pressure, the shower would turn abruptly cold sometimes (especially when you have guests), so we bootlegged a nonconserving shower head.

We have an Aquastar on-demand hot water heater. It works wonderfully, and with help from their tech support I have been able to do routine maintenance myself. My understanding is that they are more efficient and you really never run out of hot water. I believe there are Aquastar distributors in Berkeley, or one anyway. The manufacturer is in Vermont.-Jason Delborne
We have an Aquastar. Lots of hot water, anytime, and less gas usage. Because it's small, it frees up the closet where the tank heater used to be. Downsides: it was more expensive to install than we'd anticipated (substantially our contractor's fault), it requires a larger stovepipe and related hole in the roof than a regular heater needs, we have to readjust the temperature fairly often (the temperature creeps up over time), we had to put it in a very visible plce because it needs free air space for safety reasons, and you're supposed to backflush it annually (not that we ever have) to prevent clogging. Overall, if you need a new water heater, it's a good one to get. Kate
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