On 4/4/00 I watched a 1989 episode of Bob Vila's Home Again show. I came in on the program at midpoint where this New England (presumably) residential builder was discussing a novel approach to heating residences:

The hot water heater supplied a heat exchanger (radiator) with heated water via a small, thermostatically controlled pump, and a centrifugal cage blower circulated air over it to heat the house. Additionally, there was no sheet metal used in the air ducts - he just used the spaces between the ceiling, floors and joists to transfer the heated air to the various rooms of the house.

He claimed that it only cost $200 per year to heat the house (which had several other novel approaches to sealing walls, floors and windows). I assume that there are other people who have thought of this method, or that there might problems he was not talking about... such as opposition by the furnace and sheet metal PACs.

I would appreciate any thoughts on using this creative approach to home heating. This builder appeared normal on the surface...

TYVM

Richard

-- Richard (rdeegan@cprma.com), April 05, 2000

Answers

This probably won't be much help but I have heard of something like that before, except the water heater was the heat source for baseboard and radiant floor. In short, I don't see any reason why that wouldn't work provided its sized properly. Compare your existing furnace rated output and make sure the water heater is at least as big.

-- john leake (natlivent@pcpros.net), April 05, 2000.

Richard get into the search engine and look for "hydronic radiant floor" or Polaris Hydronic Heating. I have had floor heat in the past and it will be in the next. No cold floors, No blower noise No cold air blast. You will find the answer to alot of your questions at those web sites JR

-- J. R. (jr3star@earthlink.net), April 06, 2000.

My uncle used this in his in-ground house. The water heater sends hot water through pipes to "radiators" in each room. It works well he says, but costs more to operate than the dealer said it would. The heat exchanger doesn't last as long as claimed either. He is thinking about buying a bigger one next time it needs raplaced. All in all he seems satisfied with it.

-- Les (lvaughn@suntransformer.com), April 07, 2000.

Richard, you don't say what the fuel source for the water heater is. This system will not save you any money unless the water heater can provide more heat per dollar than whatever else you would be using to heat your home.

For instance, if the water heater is electric, it is 100% efficient, assuming it's not a heat pump type water heater (these are pretty unusual, in my experience).

Other types of electric heaters which are 100% efficient are base board heaters, wall mounted heaters, portable heaters (of ALL types), light bulbs, stereos, televisions, computers, etc. In short, ANY electric appliance gives off $1 worth of heat for each $1 worth of electricity it uses--WITH CERTAIN EXCEPTIONS. Some applicances lose some of the heat they produce in a way that does not help to heat your house. This makes them PERFORM as if they were less than 100% efficient. For instance, even though a electric "furnace" type central heating system is 100% efficient, it will lose a significant amount of heat through its heating ducts. If these ducts are located entirely withing your heated space, it doesn't matter; but if your ducts are in the attic, or under your floor, or (shudder) outside the house, you will be paying to heat areas you really don't want to, and so you'll be spending somewhat over $1 for each $1 of heat that actually enters your living space.

There is another exception to the rule about electric heating devices being 100% efficient: the heat pump. An outdoor, air source, heat pump can be over 200% efficent, since they are more or less "stealing" some of the heat from the outside air. They will actually give you about $2 worth of heat for each $1 you spend on electricity.

The drawback with this type of heat pump is that they become less and less efficient the colder the outside air temperature becomes. As temperatures drop colder and colder, the heat pump has to spend more and more of its time defrosting the outdoor coils. This is done by running the air conditioner phase of the heat pump, which takes heat out of your house and puts it into the outside air. To make up for this heat loss, the heat pump has to run an auxiliary heat strip, which draws a lot of power. The resulting efficiency is quite low (sorry, I don't have any figures for this, but it's way lower than for a heat pump operating in the forty to fifty degree range, where the heat pump gets its high efficiency rating.)

Another exception to the 100% rule is the "ground source" heat pump, sometimes called a "geothermal" heat pump. This heat pump operates like a "regular" heat pump, as described above, except it "steals" its heat from the ground. The fact that the ground, at depth, is typically much warmer than the outside air, enables this type of heat pump to have efficiencies of over 400%! I have one of these, and it's pretty unbelievable. There IS no auxiliary heat strip, as this system works at the same efficiency regardless of outside air temperature. My three ton unit, large enough to easily heat my 3000 sq. ft house (actually, about 1000 sq. ft. of it is only warmed, except when my wife is working in the studio) costs only 18 cents per hour to operate, and our total winter monthly heating bills are rarely exceed 25-30 bucks a month, here in relatively moderate, but nearly sunshine free SW Oregon.

Hope this helps.

JOJ

-- jumpoff joe (jumpoff@echoweb.net), April 07, 2000.

Yes these people sell what your looking for. http://www.rural-energy.com/catalog/category/22 we have 20 units asa these in our apartments but they do not make my brand (mor-Flo)They are very efficent. good luck

-- keith spaniel (kspaniel@jpusa.org), January 03, 2001.

We installed a 30 gallon L.P. gas water heater in a partially underground house with radiant heat in the floor. Nothing do the owner but to have this installed. We told'm it wouldn't heat it. The house was just too big! The waterheater was rated at 37,000 btu's. We ended up "opening up" the main burner orfice until it was at it's absolute maximum without smokin. Still it couldn't keep up in cold weather. We had also installed a forced air gas furnace upstairs [to handle a/c] while he wanted an air handler. The furnace was cheaper than the A.H. so he finally relented and went with that. It's a good thing he did----! Come next summer he had found a used hydro-therm boiler and we swapped it out with the water heater. He had heated now for about 12 years with this system. It works fine but then again-- it's big enough now to take care of the basic heat loss. On a smaller house, in a warmer climate, these work fine. Oh, BTW-this guys house was poured concrete-sett'n back in a hill, with a pond within 15 ft of the house. Guess what happened when we turned the a/c on the next summer!!!!! It "made" about 6 gallons of condensation PER HOUR!!!. Done that for better part of a week-overflfowing the drain tray under the A coil. Slowed the blower down to absolute minimum and it still overflowed and blew water into the duct system. Took about 4 weeks to dry that green crete to the point where it didn't overflow. hoot. Matt. 24;44

-- hoot (hoot@pcinetwork.com), January 03, 2001.

Richard,

My sister lived in a subdivision in Chicago where the builder guarenteed the gas bill to be less than $200/year. This was about 10 years ago. What the builder did was build a house so insulated that the only gas flame was for the water heater that required a power vent. The house was so air tight that the bathrooms did not have any vents. The hot water heater was used like you said to also heat the house. The only three problems were when taking a shower (no bathtubs were installed by the builder) in the winter, hot water was limited. The second problem is that the house never got very warm in the winter (might be because the water heater was undersized). The last problem was the biggest, on the coldest day one winter the water heater went out. It also happened to be a holiday weekend. After a while she was able to find a plumber that was willing to come and take a look and it turned out that a special electronic part for the water heater was needed. The stores did not have it and required to be fedex. It took about 3 days to get the unit back up and in the meantime we left the water dripping to prevent freezing of the pipes. We also used every electric spaceheater any family member had. To make a long story short, I am planning on using a hot water heater to also provide heat for a radiant floor system I want to install. I am lucky and live in San Francisco where in the winter it only get down to 20-30 degrees. There are many websites that talk about this (i.e. www.Radiantec.com - I was just looking at there site). I hope this helps.

Bernie

-- Bernie (bjochum@hotmail.com), January 14, 2001.