I’m in the early stages of education on designing a radiant heating system when I call my propane company in Pueblo, CO. for their input. They tell me that the propane boiler fired radiant systems in their area (south-central CO) are using “huge” amounts of propane. One contractor that builds ICF homes reports that his radiant heated homes have double the yearly heating costs compared to his homes using a forced air heating system.
What is going on here? I know that radiant costs more up front, but does it also cost more in annual heating costs? Is there an apples to apples cost comparison study that you could point me to.
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You are probably in an area where radiant isn't that common and people don't have much experience with it. If you look to the colder parts of the country you'll find that radiant is the heat of choice and the cost differance is nill if you keep the house at a constant temp.
Where there will be a cost differance is when comparing a house that has the temps yoyo greatly during the day to minimize the amount of heating. Radiant isn't very good at that since it heats up and cools slowly. The worse the insulation is, the more money would be saved by varying the temps.
In cold windy Wyoming we built a 3500 sqft ICF house that costs $600 a year to heat. There's no way forced air would have reduced that by half!
Also, beware of the inexperienced contractor. We talked with a guy who had a multi million dollar house built with radiant, but couldn't afford to use it since the slab wasn't insulated and he was heating the ground as much as his house if not more so.
In general, contractors and the propane guy are terrible sources of information so it's good that you're looking elsewhere.
I can't recommend any specific sites, but many of the most energy efficent house designs use radiant.