I was wondering if it is feasible to use an existing water heater to supply some baseboard or fan coil heating in my basement. It currently is used only to heat domestic water. The water heater is electric, and it is 80 gallons. My heating system is heat pump, and the main living quarters, upstairs is adequately heated, but the basement never reaches the same level of heat. I have considered using a gas fireplace, but that would require a LP tank, since natural gas isn't available and the house is currently electric only. The basement is usually only 4 - 6 degrees cooler than the main living quarters, so the suplemental heat wouldn't be too excessive. The area is approximately 1400 sq. ft.

Thanks for any suggestions.

You can use your water heater. I've seen raidant floorsin a small addition done that way and also the supplemental (emergency heat) heat for heat pumps. For the heat pump, the water ran through a coil in the supply phlenum. What you can also do is buy 40 gallon water heater for the basement heat but have it run in tandem w/ the 80 gal heater. You'll have more than enough hot water if you need if he heater is running at the same time. As far as type of heater if you only need a little heat, I'd go with the fan coil unit.

You may wish to check out this site, it gives you a lot of the details and what is needed to use a water heater for radiant heat

http://www.civil.uwaterloo.ca/beg/ArchTech/Hot_water_heater_Furnace.PDF#search='water%20heate r%20radiant%20heat'

I don't think there is a simple, safe way to do it. You do not want to recalculate water from a heating system back into your hot water supply. Likely, code forbids it. Better to look into carefully sealing and insulating the basement. You pay for caulk and insulation once. I am afraid all energy prices are headed up. Tighten the basement up good, and you may get away with a couple of small plug in heaters. When it comes to spare heating, about any form of electric heat, except the heat pump, all have the same efficiency.

Another point to look at would be vents, or more vents from your existing system. Does the duct work already run through the basement? Chop a few holes here and there and add vents. Very little outlay, and the heat pump efficiency. Could be the best idea unless the system is marginal for heating the rest of the house.

Actually labman this is a very common practice, they make special equipment and valves to send it though at proper pressure, and then also to mix colder water into the hotter water before it sends it to the facuet. The water heater has to be set up at higher temp.

If you follow the link I posted in my first post you will find how it works.

Now it is not cheap to set up and most likely not the first choice to do this heating but it can work

I followed that link, and it didn't look simple to me.

Ok, my son owns a construction company and at one time in my life I held plumbing and electrical licence in the state of MO.

So if you know what you are doing it is "simple" not a home do it job,

I personally would just add a radiant heat ( electric) to the basement if it is not used all the time and turn it on when I went down there.

But your idea of adding a couple more heating ducts would work geat also.

And you can add a extra duck blower in the basement duck to blow more hot air to basement.

domestic hot water and comfort hotwater don't mix together (contamination); could be done indirectly by using a heatexchange... why don't use electric baseboard?

Don't see how it can be contaminated. Its not hooked to a boiler. Its clean water that is circulating from the water heater through copper pipe, to the heater unit and back to the water heater. Where in that process would it get contaminated?

in this case it may be not contaminate BUT... if heated water is sitting inside a pipe for 3months PLUS; do you want to drink this water... also fresh water is feed to the system too often, minerals will build up and it will get air bound

I did it in a house I owned for 10 years after I installed it. Here is how I did it. Because the hot water heater was set at 120 degrees and baseboards are calculated to run at 180 degrees I added a few more feet of baseboard. I tied into the hot water line above the heater and used 1/2 inch copper to the baseboards piping from one heater to the next and returning to the cold water side of the heater. I installed a 1/25th hp. Recirculating pump to supply the heat in the hot water line going to the baseboards. To call for heat I installed a thermostat and a relay to to connect the thermostat to at 24 volts and to start the pump at 120 volts. This is a common furnace relay. My walls were insulated to R11 with a suspended ceiling. This kept my basement at up to 74 degrees or if I didn't want heat I simply turned the thermostat down and it would'nt run. I had to install a swing check valve into the cold water line close to the water heater to keep the cold water from circulating back through the hot water line. I had a 50 gallon gas heater and this system worked very well.