Better yet, replace your old water heater with a TANKLESS on demand water heater. These very energy efficient units take up less space, don't heat the water until you need it, can run on electric or gas, and are increasing in the number of models and decreasing in price now with more interest in them. Especially while many states still have tax rebates for home energy improvements, get yours today!

tank less heaters are trouble prone and the 10-15$ savings on energy is far off set by repair & maintenance I'm a retired service tech.

Researching what your next water heater will be before it fails is a good tip. Make certain in your research that you visit someone that has had whatever you pick for a few years to verify what the long-term implications are. There are countless examples where a simple green idea ends up simply not working. One example is rechargeable batteries -- they work great on a small percentage of items, but most products that you need long-term battery power for will either not work at all, or end up failing way too early.

This is not to say that we should not try these great 'green' ideas. Just be aware that you will want to test (or at least talk to others) first.

We just installed a tankless gas heater about a week ago. So far so good, since it's only a week old I can't speak for 'trouble' but we are enjoying nice hot showers. I'm not sure about the savings yet, but in our small household, not heating 40 gallons of water day and night just felt right for us (and I Love my new closet space!). I'd add that this is NOT a good DIY project for beginners. The vent had to be 5" double wall (6" here because of elevation) and not joined with the furnace, which meant installing a bulky and expensive new line, the water and gas lines had to be rerouted, and we had a dickens of a time finding a gas pressure meter that reads a water column in inches - we wound up making our own. Summary: tankless may turn out to be a big energy saver (I sure hope so), but it's Definitely something to plan in advance!!

I recently learned that there are also condensing type tankless water heaters that exceed 90 percent efficiency. They can be vented more simply with PVC just like the high efficiency furnaces.

I understand tankless heaters may last 25-30 years, and that they are widely used in Europe and Japan already-- so they are not experimental technology. Just the American plumbers need to get used to installing and servicing them! There is no tank to rust through or drain the sediment out of... they also save floor space in the home.

Even more carbon-friendly: solar hot water heating systems which reportedly may have payback times in the 5 year range. Such a system would use a holding tank and a closed loop for the thermal conducting fluid that circulates through the panel. A very weak tankless water heater could serve to top off the water heating temperature as needed.

I've had a tankless water heater for 4 years, and have had no problems at all with it. Plus~ get this~ it has cut my natural gas bills by half! I live alone so had no reason to keep a big tank of water hot 24 hrs a day. Now I have all I need and also a continuous supply when having large numbers of guests staying here. It has already paid for itself many times over. And it fits neatly on the wall by my back door in the laundry room~ where my old one was in the way.

Tankless water heaters sound like a great idea- but what about the usage ? Family of 5 , dishwasher and laundry and forget it. I have heard the usage and demand needs for this size of load would require 2 tanless heaters and installations costs would blow any payback. We have a small electric 10 gal booster (in line) at one end of our very long ranch home that prevents the running of water prior to getting in shower. then to support the heavy usage- the big 50 gal tank that kicks in when needed. It all works great.

Interesting split feedback. I installed my one tank in a 3 unit apt building, replacing 3 tanks. I've had it 4 years without any trouble. Gas fired, it serves 5 tenants (3 kitchens, three bathrooms, one shared washer) my bill averages $45 per month. I think I paid $800 for unit and installation originally. In my situation, there is one drawback. It takes time for that water to get to the 2nd and 3rd floors of a large building (mine is in the basement). I save my water when I can as it runs to get to the hot stuff and water the plants or keep it for cooking. My 3rd floor tenants probably do not. If I did it over I would centrally locate it.

#7 commented about the usage issue. No need to worry about the usage if you have a good quality tankless water heater which I have installed in my 5 bedroom house 4 years ago. We are family of 4 with two teenage daughters who love to take long shower in the morning. Typically, you don't use dishwasher and laundry and showers. Although we tend to use shower and laundry at the same time, but never had any complains so far. Technology is mature now. In fact, I remember growing up in Japan during 60s when my parents had a tankless water heater mounted right next to laundry machine which drew used hot water from Japanese style bath tub adjacent to laundry area. Americans are so acustomed to wasteful lifestyle in many ways.

The main argument for a tankless water heater is that they eliminate the standby loss of a traditional one. The additional cost of a tankless won't justify the savings in most cases though since standby losses are easily mitigated with the better insulation that new tank-style heaters have. Flow rate does adversely affect hot water output on a tankless. If you demand more water that it is rated to produce, you'll have a cold shower. This typically happens only in apartment buildings though.

The best solution is to install a solar water heater. This will pre-heat the water for whatever style of back up heater you chose to go with (tankless, natural gas, electric, waste heat, etc). The solar system will produce the majority of the heat that you'll need and extend the life of the back up heater. Additionally, there are government rebates and low interest loans for the solar water heater. To cap it all off, the solar system increases the property value of your home and RECs may be generated depending on your state. Not only is the payback immediate from a property value appreciation point of view, but you could generate additional income by selling the RECs each year.

We installed tankless a year ago and it also cut my gas bill by over half. I can have a hot shower while the washing machine and irrigation are running with no ill effect (I did have to replace my showerhead with a Speakman head for some reason my old shower head made the tank think I didn't need hot water so after a minute the shower would run cold!).

I am from the UK where it is the norm to have a tankless heater (I'll admit I was horrified to move here and see these prehistoric monsters hiding in garages gurgling all night long) and because of that, there tends to be a lot more choice of heaters that are able to accommodate bigger or smaller demands depending on a household's needs.

If the US consumer would take the brave plunge and embrace tankless, then the model/manufacturer choice in this country would increase dramatically.

Interesting...I had no idea they were so prevalent in Europe! Well, I don't have one, though I had planned on getting one when I finally build a house, but I have a lot of doubts now.

My parents got one just over a year ago, and though there is hot water in the sinks, and downstairs bathtub, there is NEVER hot water in the shower upstairs! Well, I shouldn't say "never" -- for each shower, you probably get about 30 seconds of hot water, and maybe 2-3 minutes of lukewarm. The rest is freezing cold. (It's not constant -- the heat cuts in and out the whole time, and it does not seem to depend on flow.) My mom at first thought it was because it was winter, and the line wasn't insulated enough, but apparently it has stayed the same through all this summer as well.

We did change the showerhead (the old one was clogged anyway), but it did not seem to make any difference.

I love the idea of the savings, and not wasting energy, but I love my hot showers more -- especially in the winter!

Rose,

Try a Speakman showerhead in your mother's shower. The problem she is experiencing sounds exactly like the problem I had. My plumber came out and suggested it and it worked. I think the Speakman heads aren't as water saving as other heads though which kind of cancels out my smug feeling about using less gas!

Consumer Reports magazine has a two-page article on tankless water heaters in its Oct 2008 issue (pp 28-29). Bottom line is they don't recommend them (yet). They contend that, because they cost much more than storage water heaters, it can take up to 22 years to break even -- longer than the 20 year life of many models. Also, unless the tankless heater is right at the sink/shower/appliance, the cold water in the lines still has to empty out before the hot water reaches the spigot. Colder climates have colder ground water, so efficiency can be worse than in warmer climates. Scale buildup can also be a problem, which may necessitate a water softener. Electric tankless heaters are not at all efficient; gas tankless heaters are much better, and use much less gas than tank heaters, if you don't mind the long term payback.

We have a tank heater that we must keep higher than 120 degrees. At 120, we noticed our hot water smelled bad. A plumber friend told us to obtain a special anode for the tank (aluminum, as I recall) and to turn up the heat a bit, which has worked great. The smell was caused by a bacteria which is harmless, but nonetheless unpleasant.

We don't have gas lines, so tankless is not an option, unless they improve the efficiency of electric tankless, or we assume the expense of installing an underground (required in our neighborhood) propane tank. Maybe if we were not retrofitting our home, but rather building from scratch, tankless could be justified.....