I am kicking around the thought of radiant heat in part of my home. I just wondered if anyone out there had any ideas for home brew equipment PEACE TO ALL john

-- john d.hayes (jdhayes@adelphia.net), November 28, 2001

Answers

I have built two Russian Masonry furnaces and I highly recommend them as radiant heating devices. Do a web search and you'll find designs.

-- oxman (singingfalls@tymewyse.com), November 28, 2001.

We've been considering that as well. We were thinking that we could use it to distribute heat from the wood stove. We'll be getting a stove that is designed to accept a water heater insert in the firebox, and using a circulating pump to keep things flowing. We would be running the floor in the Kitchen, bathroom, den, and back sunroom, with seperate loops for each room, so we wouldn't have to heat a room we weren't using at the time. We've also been considering using an old well on the property as a heat sink during the summer months, and running cold well water through the floor to keep things cool in the house.

-- Connie (Connie@lunehaven.com), December 04, 2001.

Just a little reading on the web points out the problems with putting a heat exchanger in the fire box. This will cool the combustion chamber below the optimal temperatures for COMPLETE combustion. The result will be much more smoke and build-up in the chimney with possibly catastophic results. Complete combustion ONLY results if the firebox is masonry to the point that all gasses are completely burned. The second concept of circulating cold water through the floor will result in a very uncomfortable situation unless there is NO humidity in the air. Our house is earth sheltered and since the floor is more than four feet below the surface the floor tempearature is quite constant at 55 to 60 degrees. This causes dehumidifier use and a significant electric bill. I hope to hydronically heat the floor soon and in the summer I hope to heat it with solar hot water. Jade Mountain has a very good hydronic heating book that will work you through the ins and outs of heating the floor. Materials required and the differences between the cheap and the good. They have a web site. http://www.jademountain.com/

-- kirby johnson (kirbyj@deskmedia.com), December 18, 2001.

Hi John. I had to get rid of my wood floor in the attached sunroom [wood stove insurance]. So I clean it out to the ground, lay in 3" insulation, some plastic. This is where The wife gets nervous. The cost of concrete and the pumping I mean. I get this idea see, I loop in some 4" drainage tile, connect it to a square Tide plastic bucket and point the other end[s] up into the room. Shovel in 14 ton sand. Mix 60 bags ready-mix concrete, screed, stamp with one of those plastic "walk makers" then stain the "stones". Hang with me. I put a small centrifugal fan atop the sunken Tide bucket which is behind the woodstove. Since I try to burn only hot fires, the excess heat gets blown into the sand. The intake duct rises to the ceiling and is ugly but The wife understands. She has a warm floor AND tropicals. Gloat gloat. P.S No plastic smells so far.

-- Virgil Wright (VIRGNMARI@dragonbbs.com), December 21, 2001.

Hello John, I have a concrete slab with hot water through standard PVC (yes not CPVC) piping that heats a greenhouse and an ajoining 1400 sq ft office building. I have free wood from my farm. I did not use foam board insulation under the slab but would have if not for the free wood. I used 3/4 inch PVC spaced 12 inches on center. I have several zones, the largest covers 240 sq ft of floor - don't go any bigger. In the bathroom I spaced the piping 6 inch on center to have a nice warm floor for the shower. Because I used PVC I have a vented (no pressure) hot water heater and I limit the water temperature to 140 deg F maximum. In practice the water never gets above 120 deg F which is good as the PVC gets a little soft and I feel it may slowly deform at the higher temperatures. The system has an LP gas boiler as backup but I haven't used it for 3 years since I got the Hardy wood burning heater going. I have 2 pumps, one on the Hardy to transfer hot water to the suction manifold and one circulating pump to distribute water through the gas backup heater and on to the supply manifold. The manifolds are 1-1/4 inch PVC and the weakest piping in the system. The pumps are Grundfos type UPS15-42F and draw 45 Watts each on low speed. Therefore the system requires 90 Watts total and costs $6.48 to run for 30 days at $0.10 per KWHr. I plan to add a PIC micro- controller to the system and believe with that I can optimize my fuel and reduce the running cost by at least half. If I can get the heating cost under $4.00 per month i.e. $1.00 per week, I will feel good about my investment.

When I build my house I will use CPVC and put 2 inches of foam under the slab. Need to use high density foam of sufficient compressive strength for the load. I have the design information but I am growing tired of typing and my wife wants me to come eat - hope this helps someone...

-- John Hayes (jehayes54@hotmail.com), January 02, 2002.