Tankless, on demand, water heaters

Ida, MI

I just had my propane delivered and I only used 111 gallons since mid November! Of course I have my mighty woodburning stove to thank for keeping my home warm and toasty throughout subzero temps this winter but I also installed a tankless water heater a couple of years ago and it is definately providing me with substantial propane savings while IMPROVING our quality of life. First, it only heats the water when you need it, it doesn't keep thirty or forty gallons of water hot just in case you might need it. That is what a standard water heater d0oes. A tankless water heater only heats the water when you are ready to use it. I used to keep my water heater turned way down to save propane, this meant that when you took a shower you could only get it as hot as the water heater was set which wasn't that hot. The other problem with standard water heaters is that you run out of hot water! If two people wanted to take a shower in the am the second person had to wait for the water in the tank to heat up. No more! With the tanless you have endless hot water! And I don't mind if the kids take a longer shower because I know I am still saving money compared to the old heater keeping the water hot all day and night.

Not to mention since there is no tank to rust out, these things last a lot longer than the older models and when they do go, its a small plastic box with cooper pipe which can all be recycled and even if its not it is still MUCH smaller than a big tank. Thats another plus if your house is short on space, it is a small box that hangs on the wall, it actually takes up ZERO floor space. I got mine at Lowes and had a handy friend install it, he was so impressed he went out and got one for his own house. They come in natural gas and propane models and I believe there are electric models also. You can even get small under sink models for say a bathroom sink in an office etc. IMHO these things are a perfect example of sustainable alternatives, while it doesn't eliminate your need for propane etc. it deffinately reduces that need and IMPROVES your quality of life. IMHO tank style water heaters are a dying breed, the tankless style will soon replace them.

Josephine, Arlington, TX(Zone 8a)

Sounds like a very good idea. We will have to get one of those when the one we have gives out.

Belfield, ND(Zone 4a)

Great information. We have been thinking of looking into the Hot Water on Demand thing, but really don't know anything about them.

We have an 80 gallon water heater, and since our daughter moved back home, and when our son is home from college there is never enough hot water. Between the washing machine, dishwasher and showers, it seems one or two of them are running day and night.

Alexandria, IN(Zone 6a)

Does anyone know if these tankless models can lime up if soft water is not used?

Missouri City, TX

I had real problems in Houston, years ago. No problem with, or in the heater itself, but the calcium and mineral deposits clogged every sink and shower aerator. Had to backflush the hot water lines every 2 weeks to have any usable flow.

But when clear - you could open every hot water tap in the house and NEVER run out. Had adjustment for 70 to 90 degree rise in input temperature.
125,000 BTU burner, required 5" or better vent.
Some new ones have only a 4" vent, so no extra work on the roof.

When the existing traditional HW heater dies, I will put a softener in line and reinstall in this house.

Ida, MI

All a tankless hot water heater is is copper pipe with a burner around it. I can't imagine that hard water would affect it any different than any other copper pipe. Hard water greatly reduces the efficiency of a tank style heater by forming deposits and making it harder to heat the water. I'm no plumber but in theory it would make sense that a tankless would be better in hard water than a tank style. Are you saying bubba that you uninstalled the tankless water heater because of the clogging? Or are you refering to installing one in a different house?
Joan, an 80 gallon water heater and you are still running out of hot water? Yikes! Run don't walk down to lowes and get you the large size tankless. They come in two sizes. With the smaller size you can have one major hot water draw at a time, like taking a shower, and a smaller one like washing hands. The larger size allows for two or three major hot water draws at the same time. I have the smaller one, with the water pressure in this house you couldn't do two major things at once if you wanted too. But with the larger one you could have both kids in the shower and wash your hands all day 7 days a week and never run out of hot water. And an 80 gallon hot water heater sucks up a lot of wasted energy when its not in use, my guess is it would probably save you some cash in your energy bills.

Belfield, ND(Zone 4a)

Thanks spot! You gave me a place to start looking anyway. I didn't have any idea. We'll stop at Lowes the next time we are in Bismarck.

Ida, MI

No problem Joan. I have been very happy with mine, I recomend them to everyone. The model Lowes sells is Bosch, I think there are other brand names out there but I can only personally speak of the Bosch. I found a site with more info. and you can even order them online, though I think lowes price might be a little better but this site does carry reconditioned models.


Burlingame, CA(Zone 9a)

I had a tankless water heater installed in my last house at the same time as having a gas furnace installed. It was the best investment I've ever made and I am in the process of researching the models again to have one installed in this house. Not only is having endless hot water on tap wonderful but getting back the space in my laundry where the tank sits is going to be fantastic. One other thing that hasn;t been mentioned is that you can get temperature controllers for them which in a house with young kids is great. I set the temp on the controller and there is no way they can burn themselves if the play with or knock the faucet handle in the shower.

Edited to say: I had a Rheem model

This message was edited Mar 13, 2007 7:44 PM

Rose Lodge, OR(Zone 8b)

spot, you have been infinitely helpful as i contemplate practically razing my house. I can't afford to cherry this one out like I did the previous one because I'm not working full time anymore, but I'm going to put my money where it will help most.

So your stove & tankless heater will be at the top of the "must" list.
It's so daunting to consider all the options & costs when wanting to build sustainably.

Ida, MI

Summer, when we bought this house in 91 it was a mess. Very well built and solid structurally but maint had been let slide and many components were past their normal lifespan. Over the years it has been gutters, roof, furnace, pressure tank, plumbing, windows, insulation, etc. etc. etc. and I'm still working on it as time and money permit.

My personal strategy is to develope an overall plan, then hit the things that can't wait. For example when we bought the house the gutters were metal and had rusted through everywhere, as a result water was pooling around the foundation, freezing and beginning to bow the basement walls. It also resulted in a LOT of water in the basement! This was a project that would have cost far more to put off than to do it fast. Then when those projects are taken care of I focus on anything that will save me money in the long run, focusing on the ones with the biggest potential savings first. Also smaller projects that don't take a lot of cash. I try to do as much as I can myself to save money, plus it makes me feel good to know I did it myself. Its amazing how much you can accomplish with a readers digest home repair book and a lot of determination! LOL The water heater was on the list as a desirable, but when the old one broke it became a necessistity. Sometimes your plans have to be adjusted. I still have a lot of work to do on 'this old house' but I am already enjoying savings from previous projects which helps fund future ones. Anyhow, thats my personal strategy. Asthetics can wait if they are costly. Just take it a step at a time and consider it a fun challenge. I honestly don't know what I would ever do if I ran out of projects, probably move like I did the last time. LOL

Rose Lodge, OR(Zone 8b)

I just posted pix of the house that I fixed up in a different thread, and I'll be documenting the rehab plan for this one because a fellow DGer is going to lend her architectural expertise.

It's unlikely that I'll stay in this house more than a couple of years, so it's going to happen all at once so that I'll have a nice property to sell when I get ready to move back West.

I'm taking welding, Autocad, jobsite management & electrical classes at the local community college, so that's a great help.

Nth Coast NSW, Australia

I use a tankless heater much the same as those mentioned above, an aussie brand, and, call me mean if you will, I turn off the pilot light and just light it up when we shower or do the washing up- saves heaps of gas, and heaps of money.

Missouri City, TX

I installed the tankless when the original sprung a leak and was full of scale. I removed and reinstalled a conventional heater when we sold the house. But, I kept the tankless for a future house. My job provided me with a few moves, so I did not reinstall it in any of the houses I rented or bought.

Now that we are adding improvements every couple of years to our present house, I will probably reinstall it, but will use either a filtration system or water softener in line with it. I have no desire to repeat the backflushing again. I have had to do a bunch of retro-plumbing on this house, as is.

Josephine, Arlington, TX(Zone 8a)

Summerkid, please show us the pictures of your house improvements.

So.App.Mtns., United States(Zone 5b)

I just found this thread. I did a LOT of research 3-4 weeks ago when my water heater burned out the heating element. My sis owns this house even though she hasn;t moved here yet, but she'd like tankless, so I did my homework.

We won't install one until we can replace all the crappy undersized water pipes, maybe this summer. But here are some important features and differences.

First, better ones now come with filters for scale/lime build-up, or you can add one.

Second, you can do a single whole-house tankless heater, or add one in every bath/laundry/kitchen that uses hot water. For larger houses or those with long plumbing runs to bathrooms at the other end of the house, most manufacturers recommend adding an auxillary pump kinda thing.

Frankly, I'm leaning towards one in every bath, etc. Those run on 115 volts and simply plug in, whereas the whole house units run on 220v. I can install and hookup the single units myself, no need for an electrician and a plumber.

Now having said all that... if I were doing a dwelling almost from scratch, I would have an exterior wood-fired boiler to provide heat in the floors and hot water to bathe, cook, and do laundry. Heck, I'd even use it to heat a greenhouse!

Solar hot water is not too viable in my climate with cloudy days and freezing temps in winter which would require a sophisticated closed-loop system. However, I have toyed with a summer system which I could do for pennies, and switch back in late fall. I grew up with solar hot water and we seldom had to run the auxillary heater except for prolonged rainy days even with 4 in the house.

Rose Lodge, OR(Zone 8b)

Here is a thread with pix of the house I just sold after fixing it up for 10 years. Unfortunately, I never took any before pix. But it will give you an idea of my tastes & proclivities. Tonight or tomorrow I will be posting pix of the shack for which I'm setting up to do a rehab. First project will be turning one end of the garage into a self-contained studio for my artwork & living space during the construction. The garage is 57 feet long! Dang hillbillies.

(this photo thread is an adjunct to another one peopled by some folks who have struggled with situational or chemical depression & we just chat all day long. good group.)


Deep East Texas, TX(Zone 8a)

Spot ~ your comment

I just had my propane delivered and I only used 111 gallons since mid November!
as opposed to how much consumption previously with the old water heater? I am curious because I am wanting a propane tankless water heater. Our water leaves lots of scale and mineral deposits. We currently use an electric water heater and replace burned out elements on a regular basis. The tank capacity (if not flushed) will become much smaller because of the mineral deposits and the water volume will become much less. By not having to maintain a water temperature I am sure this system will be far more efficient.

Greensboro, AL

Spot8907: One of the burners on my electric hot water heater gave out several months ago because of a lightening strike. I have been shuffling and shuffling trying to figure out how I will get a natural gas water heater which will be several hundred dollars. The electric right now heats only a few gallons at a time. To do the dishes I have to do one dishpanful, then wait to til the water reheats. (The lightning strike also got the wiring to the dishwasher). I have dreams of having a full bathtub of hot water. Hmmm. Have you solved my problem? Have you changed my life?

Do you know that one of the true joys of life is working out side and getting really dirty and then taking a shower or a bath with LOTS of hot water?

Delray Beach, FL(Zone 10a)

I live in Fort Lauderdale, Florida. We remodeled the kitchen in July 2006 and installed an electric on-demand instant-hot water heater. We are delighted but there is one important drawback to the system.

The unit has a built-in safety feature that shuts off the heat to the unit when the temperature inside the twin heating chambers gets too hot. Since water in South Florida doesn't ever get really cold, very little hot water is required to shower. The water would flow slowly in the heating chambers and get too hot, somehow. Then, the safety feature would kick in and completely shut off the water heater. You would end up showering with cold water for about a minute before the safety feature kicked off again and the heater started heating up again. The shower wasn't pulling enough hot water for the heater to work continuously.

To avoid that, we had to run the hot water in the kitchen while showering, which defeats the energy savings. As a last resolt, I removed the built-in water flow restrictors in the showerhead. That settled it. OK, I use more water than what Water Pik intended (2.5gpm) but I save water by drinking wine and beer. We all do our bit some way or another, I guess. I also turned down the unit's thermostat, thereby producing hot rather than scalding water. Aside from that, the water heater is wonderful and I heartily recommend them.


Alexandria, IN(Zone 6a)

gloria 125,
Does your electric transformer on your light pole have a lightening arrester?

Greensboro, AL

Don't know. I live within the City limits. When the power goes out, this whole section of town goes. Usually, we have a power outage two or three times a year. The light pole that has the transformer is out on the street. The lightening strike that did in my water heater, hit the fuse box. Not all the fuses were affected, just to one side of the house.

New question about tankless water heaters. I notice the natural gas units have electronic ignitions. Doesn't that mean no hot water if there is a power outage?

Ida, MI

Podster, it is hard to say exactly how much propane savings is from my water heater as I installed a woodburning stove soon after I got the water heater, but I do know they used to fill my tank in sept after the summer months but now it is typicaly late Oct. To mid november.Here is a little speel from the Bosch website.

Energy Savings of up to 50%
Your water heater is the second largest consumer of energy in your home after home heating/cooling. Therefore, it is where you can significantly reduce the costs of your annual energy consumption. Why keep a storage tank full of hot water 24 hours a day when the average household use is less than one hour per day?

When water is heated and stored in a tank the inside walls will soon begin to build up mineral deposits. The scale build-up on the bottom of the tank can cause it to decrease in efficiency by as much as 50% over 10 years and the subsequent corrosion of the tank's inside wall will eventually cause it to leak. Compare this to a tankless water heater which does not store water and maintains its efficiency for the lifetime of the unit.

And the webpage.

Now bubba stated that he also had hard water and he had to backflush his, so you might want to discuss the issue with him. I also have hard water but I use a water softener, another product I really like but It doesn't relate to sustainability unless you want to count that it improves the life of your appliances, particularly your water heater. Well also you use FAR less soaps and detergents but then again it uses salt to clean the medium so your putting salt into the environment but the newer models don't use as much as the old. Tradeoff I guess.

Ida, MI

Gloria, one of things I didn't like about mine was that it has a pilot light, I would much rather have gotten electronic ignition to save on the propane. But I notice on their website that bosch now has units that use the flow of the water to somehow create ignition, this would mean no pilot light and you would still have hot water during a power outage, best of both worlds, wish I had one. But I would never replace anything still working simply for the pilot light issue. But if I were to buy one today, that would be the model I would want.

Greensboro, AL


This is the Bosch Hydro Ignition System water heater.

Ida, MI

Gloria, you mentioned money being an issue, check this out.

2007 Tax Credit

See: www.energy.gov
See also: www.gamanet.org

Energy Efficient Bosch Water Heaters Can Save You $300 on Your 2006-2007 Taxes

Waitsfield, Vt. — Start the New Year off right by purchasing a highly energy-efficient Bosch tankless water heater. Thanks to the Energy Policy Act of 2005, passed by Congress and signed into law by President Bush, homeowners who have a Bosch gas water heater with an Energy Factor of 0.80 or greater installed in their home in 2006/2007 are eligible for a $300 tax credit on their 2006/2007 income taxes.

One of the primary goals of the Energy Bill, which took effect on January 1, 2006, is to reduce America’s energy consumption. To accomplish this goal, it includes incentives for U.S. consumers to use more energy-efficient products and technologies.

Residential water heating is typically the second largest use of energy in American homes, so the Energy Bill includes a special provision to encourage homeowners to use energy efficient tankless water heaters like those produced by Bosch. This is actually a win-win-win for homeowners, who can now receive a tax credit for purchasing a Bosch tankless water heater which can lead to a reduction of 30%-50% in monthly utility bills while helping to preserve the environment.

Only gas tankless water heaters with an Energy Factor (EF) of at least 0.80, as certified by the U.S. Department of Energy, qualify for the tax credit. The Bosch product line includes sixteen powerful, energy-efficient tankless water heaters with EF’s above the 0.80 minimum: Ask your plumber for Bosch tankless water heaters. Standard, old-fashioned storage tank heaters have lower Energy Factors because they heat water continuously, whether it is being used or not. “That’s like leaving your car idling in the driveway 24 hours a day,” noted Kyle Murray, Vice President of Marketing for Bosch Water Heating. Bosch tankless water heaters have EF’s as much as 20 points higher than even the best storage tank heaters.

Tax credits are far from the only benefit enjoyed by homeowners who use Bosch tankless water heaters, of course. These water heaters produce an endless flow of hot water, and only heat that water while it is actually being used. The new generation of Bosch tankless water heaters produces flow volumes of almost seven gallons per minute, which is enough for two major simultaneous household uses such as showers, laundry, dish washing, etc. And Bosch tankless water heaters are as environmentally friendly as they are efficient, producing up to 50% fewer greenhouse gas emissions than less efficient storage tank heaters.

Contractors who build energy-efficient new homes or commercial buildings, or who remodel older buildings, are also eligible for tax incentives under the provisions of the new Energy Bill. This tax credit will continue through Dec. 31, 2007. It is possible that the program will be renewed thereafter. A total cap of $500 in credits per individual is allowable under the current law, with additional credits and requirements involved.

Contact: Maryke Gillis
[email protected]


So.App.Mtns., United States(Zone 5b)

Good information, Thanks.

Greensboro, AL

I noticed on the Bosch Hot Water site, that they also manufacture floor heating equipment for heating with hot water. After a winter of getting purple lesions on my feet from the cold, that sounds like a good idea, to go with the instant hot water.

thanks, Spot.

Ida, MI

Your welcome Gloria. I have been very pleased with mine, just having endless hot water when you need it is wonderfull. Then add to that the environmental and financial benifits I consider it one of the best purchases I have ever made, I think these things deserve far more attention than they are getting so I am just trying to help get the word out. Apparently these things have popular in europe for quite some time, they deserve the same popularity in the US.

Greensboro, AL

Im still looking to see if the instant hot water heaters can be used for radiant heat of tile floors. I need a new kitchen floor, too. But, then I read that the trend is to heat floors with dry air, not hot water. Im still researching that. But, youve got me off and running, Spot. Sounds like a great rehab project. Hot water, install the new dishwasher sitting in my garage, new tile floors that are warm in winter. That would make a big difference to this 100 year old house.

San Francisco Bay Ar, CA(Zone 9b)

You bring up a good point gloria. I have a hydronic heating system that heats the house using the hot water from the water heater. It is an energy efficient system for heating, but it does use a conventional hot water tank. I'll need to check into the ability to convert it to an on demand type of hot water tank when the current one needs replacing.

Ida, MI

That's what's so wonderfull about a forum like this, hearing from people who are or have done projects really gives you motivation. I have been planning on installing rainwater catchment for a couple of years, just haven't been motivated enough, now after hearing and seeing other peoples projects and getting new ideas I'm motivated to take on a much bigger project than I originally considered. It also helps to avoid mistakes you might otherwise make by hearing of the mistakes of others and getting feedback on your ideas. This is something you can't get from a book. The more people who actually implement these ideas the more of an impact it makes. Kudos for whoever got the idea to start this forum, I can't remember who it was but thanks!

Greensboro, AL

Dave started the forum. Spot started the thread.

Alexandria, IN(Zone 6a)

Hard water areas like mine are bad for deposits in conventional water heaters unless the water is softened or treated or drawn from softer water sourves.

So when my 52 gallon electric water heater had its first problem [bottom element burned out] after just over 30 years, I expected to find a build up in the bottom........only about ¼ inch!

So.App.Mtns., United States(Zone 5b)

Gloria, actually I think I was the impetus for this forum, and then Dave implemented it.

Greensboro, AL

Great idea, Darius.

So.App.Mtns., United States(Zone 5b)

Do not misunderstand me... in no way do I want anything but for this forum to encourage dialog and sharing information so we ALL can benefit.

(I'm just having a bad day... the last of my mother's siblings isn't expected to live out the day.)

Greensboro, AL

So hard to fathom the significance of someone's life when there is so little left of it. Sorry you have this sadness for today.

Lower Hudson Valley, NY(Zone 6b)

I have had a Bosch natural gas model (the smaller one - when I got mine it was the only one available) with a battery ignition - no pilot light. I love it. I just wish the larger unit was available back then. As spot said, only one hot water use at a time. It must have saved me oodles over the seven years I've had it.

Greensboro, AL

Victorgardener: I thought I did a pretty thorough review of the Bosch water heaters. Ive seen electronic ignition, hydronic ignition, but no battery ignition. Can you elaborate please?

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