Ken Dunn wrote:
> 7. What is the group's collective experience?
I have radiant hot water heat in my house and I'm happy enough with
the system to say that I don't wish to live WITHOUT radiant heat in
the future. It's probably colder where you live during the winter
than it is here on the left coast, and the colder your climate, the
faster the energy savings of radiant heat will pay back.
We installed the plastic tubing directly beneath the floor boards on
our upper floor, which was a LOT of shoulder and back breaking work!
Doing this enables our upper floor to heat quickly, giving our system
a faster overall response time. If you do this, however, you'll want
to install grommets in the floor joists. We didn't, so whenever the
boiler fires up, the plastic pipes tap against the joists. It sounds
like a myriad of golf balls bouncing on the floor--not altogether
unpleasant, but certainly something unnecessary.
Our lower floor has its tubing buried directly in the foundation
concrete. It heats up slower, but also cools down slower, so the
lower floor of the house stays at a very even temperature throughout
the heating season. If you can do fibernet concrete in your
installation, I would recommend it.
Radiant floor heat is very comfortable and energy efficient. Our
house, which is among the smallest in our neighborhood, uses about
forty percent of the energy for heating of a comparably sized home
with forced air, and considerably less than the towering behemoths
that populate our subdivision. Part of that greater efficiency,
however, may stem from the fact that I sealed every join between floor
and wall and caulked around every window when we built the house.
(The carpenters thought I was crazy, but then, so does everyone else!)
We also have R 50 cellulose blown into our attic. Our house stays
nice and warm when it's cold outside, even in the nearly constant,
prevailing wind that blows around up here during the winter.
Another nice feature of radiant heat, is that the propylene glycol /
water mix (don't use ethylene glycol) can be heated by a variety of
means. You can set your boiler to heat an insulated storage tank and
put in an extra coil for solar input. If the thermostat on the
storage tank is set for a given temperature, your boiler will only
activate when the solar thermal energy has been used first. In
theory, you could tap heat from the tank for domestic hot water as
well, so a single system could serve home heating and water heating.
Most good boilers are more efficient than water heater tanks,
engendering another savings (albeit a small one) down the road.
Disadvantages include:
1. The potential for structural damage with a leak. A properly
designed system SHOULDN'T leak, but then, I live in earthquake
country and we have to take that risk seriously.
2. Greater initial expense for radiant heat.
3. Lag time between outdoor temperature drops and the response of
the system.
4. Wood fired boilers pollute more than wood fired forced air
systems because water is much more efficient at removing heat
energy from the fire box. This can also result in creosote
build up.
If I were to build another house, I would use solar thermal storage
in the foundation mass, coupled with a gasifying boiler and radiant
heat. That would be efficient to operate and inexpensive to run.
> 8. Might I be better off building a window mounted solar collector
> initially?
This might overheat the room if you're not careful.
> 9. Are there other more efficient solutions?
Start with insulation and draft proofing. Get good windows and use
window quilts wherever possible. Once you've taken care of these
easily implemented, affordable solutions, the rest will cost less
money and involve less work.
robert luis rabello
"The Edge of Justice"
Adventure for Your Mind
http://www.newadventure.ca
Ranger Supercharger Project Page
http://www.members.shaw.ca/rabello/
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