Hydronic heating?

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Does anyone have any experience with hydronic heating? Typically this is the type of heating system in which heating pipes of some sort are run through a concrete floor, thereby achieving thermal mass. If anyone gets the Jade Mountain catalog they can find info on this. One excerpt claims that the water or liquid in this type of system can be heated by Thermomax solar collectors on the roof of the house. See page 190 of the 2001-2002 catalog. Anyone know of successfull applications of this technology? If you don't have the catalog it can be ordered at 1-800-442-1972. Their website is www.jademountain.com. The upfront costs are high but the long-term payoff would be worth it to me...not having to chop and split wood or deal with cleaning creosote out of the stove. I could be getting heated water for personal use too. Also, from a health perspective this is the best type of heat to have.

-- John Fritz (JohnFritz242@hotmail.com), November 27, 2001


If you're using piped heated water the water has to be heated somehow. Now, it could be a furnace or a woodstove or a propane- burner or whatever. However, if you're thinking solar heating, I'd do some real careful investigation on how many hours of clear-sky daylight per day you'd get during winter, and basically whether it would do the job. I might get away with it, but I kinda think most of the USA couldn't.

-- Don Armstrong (from Australia) (darmst@yahoo.com.au), November 27, 2001.

Actually it's called radiant heat. Hydronic is just a general term for water in the heat pipes as opposed to forced warm air. There are many good ways to heat water for " in floor" heating because typically the water temperature has to only be about 120-130 degrees... much lower than a regular boiler that maintains 190+ temperature. I plumbed a house in Bangor Maine about 8 years ago that had a combination of solar panels and a gas boiler. It does get very complicated for the imstrumentation to control this type of a system. Not only do you have to be concerned with not enough sun but you also have to have a dump zone when you have too much sun and an excess of temperature in your water storage. Depending on the size house ( for instance) a 3 bedroom ranch you could get by with a unit not much more complicated than a regular water heater. They are manufacture with two separate interior piping schemes. That way domestic water doesn't get contaminated with the in floor water. They are pretty slick and only require an exhaust vent for combustion. It's a tube within a tube. Exhaust and make up air. There are examples of super insulated houses ( 12 inch walls) that utilize only $250/300 for an entire year. And that's here in Maine. Those are older figures ( from 1995) but there shouldn't be too much difference now. It's a fun system to engineer and play with!

-- Ken in Maine (kenjan@nh.adelphia.net), November 27, 2001.

Back in 1995 when I built my house, I installed radiant heat in the basement. I used a product from Heatway. It consists of a series of flexible rubber tubing run through the concrete. The tubing itself wasn't hard to install, however the above floor plumbing was a little more difficult. The system is hooked up to a Bradford-White Combi- cor water heater(a plastic tube spiriled(sp.) inside a gas direct vent water heater) with the usual relays and pumps. The system works quite well as the basement is always 70* and you can walk around in bare feet. The system cost me around $2000 to do it myself and is well worth every penny. Don't know how much it costs to run as I also use gas for stove and domestic hot water. Emory

-- Emory (NE PA) (et@hazleton.net), November 27, 2001.

Ken, I'm curious, what are the super insulated homes you mention with the twelve inch thick walls constructed of? is this a conventional stick built home? Thanks, Brad

-- BF Morris (chelone@cci-29palms.com), November 27, 2001.

I did some work for a fellow from Clinton or Benton Maine that had a type of truss design that he built with. Basically he took the equivalent of a TJI truss ( 2bys with plywood webbing ) and used them for his stud walls. It seemed to work rather well. He then loaded the outside walls with fiberglass batts. He used a monolithic slab with radiant heat. It was a fairly good system. We did some houses in Fairfield, Maine... Bangor and Indian Township near Bar Harbor.

-- Ken in Maine (kenjan@nh.adelphia.net), November 27, 2001.

I've got a two-zone radiant/hydronic system. Heat source is the outdoor wood boiler. One zone is the floor in the basement family room and shop. The other zone is an air to water heat exchanger in the plenum for heating the upstairs. There's also a 700 gallon water tank that'll be used in conjunction with the solar system and boiler. The solar system will be installed next summer.

-- john (natlivent@pcpros.net), November 28, 2001.

John, What kind of tank are you using for the seven hundred gallons? Sounds like an excellent idea using solar in the summer, and the seven hundred gallons of hot water is for domestic use correct? Thanks, Brad

-- BF Morris (chelone@cci-29palms.com), November 28, 2001.

Brad---the tank is a concrete block tank. We filled the cores with cement and coated it with a waterproofer that would handle higher temps. If I had it to do again I'd locate an old stainless steel bulk tank used in a dairy operation. They offer several advantages--- already insulated, plumbing fittings already installed and will never corrode or leak not to mention they can be had for pretty cheap.

Another possibility would be a new septic tank.

I'll not only use it for summer heat storage but also as a heat sink for the boiler/solar collectors. I figure it'll enable me to store 2- 3 days worth of heat so we can leave the house in the winter for a couple days without having to worry about coming home to a cold house.

-- john (natlivent@pcpros.net), November 28, 2001.

We built an earth contact home, 3200 sq ft. We used geothermal runs and have a water-water heat exchanger. Then ran radiant heat in four zones. The dicey thing was running the tubes, with a spray paint layout of the house on the starfoam insulator board which lined the floor. Then pouring the concrete, then putting up the stud walls without putting a nail through one of the tubes! We actually missed all of the tubing. What luck.

The heat is WONDERFUL! No drafts, since the heat comes from the floor up, all of the furniture is warm, even the toilets....which my wife appreciates! Truely is the best system we have ever had. Love walking around in stocking feet, feeling the warmth of the floor on your feet. You can tell where the warm spots are....the dogs lay on those!

We also install windows from Pella, specially made for radiant heat. The home is well insulated and very tight. We have a wood stove for backup, but have only used esthetically.

-- Rickstir (rpowell@email.ccis.edu), November 28, 2001.

I installed kitec tubing in my concrete slab in my basement. I also put it on my main floor and poured a light weight concrete over it. I'am using a high efficiency hot water to heat my home as well as my domestic hot water. We live in Michigans Upper Peninsula where temperatures drop to well below zero in the winter. I pre buy my propane and spend $1000 a calendar year for heat and hot water. Something I would recommend is to not skimp on the insulation of walls, floors, roof etc. It is a very nice even heat and very easy to do yourself. A question I have is the installation of a water tank or boilermate? Any comments on this would be appreciated.

-- Daniel Mills (cndmills@jamadots.com), December 05, 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. Also I use rain water to prevent scale in the boilers. It is 10 degrees F outside right now and I am nice and warm. The hot water is running at 108 degrees F and my feet feel great. 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.

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