If one were going to build a home today in an exclusive (multi-million
$) housing area between 6,500 and 7,000 foot altitude, what would be
considered state-of-the-art in heating systems? This area gets heavy
snow in the winter. Also, considering that the house is pretty
high-end, would it be common to forget about air conditioning even
though there would be some pretty warm days in the summer?
Have they gotten more cost effective? After geothermal, a good solar system
but that depends on how much sun you get too. In any case, the system should
have backup if power lines are down or it would not be so state of the art.
In addition to a good heating system, I'd want state of the art construction
for maximum thermal efficiency using something like ICFs (insulating
concrete forms) www.polysteel.com or www.integraspec.com
Over a long period of time, they can be cost effective. Even if you have to
change out the equipment after 15 years, you can still use the existing
ground loop. In any case, the OP simply asked for a state of the art heating
system in exclusive (multi-million $) housing area. He didn't ask about
price or cost effectiveness.
If done right, the air temps coming out a geothermal are much warmer than an
air-to-air heat pump and he'd have built-in air conditioning. If he were to
build that type of house with no duct work, you'd have a hard time
re-selling, especially if they get "some pretty warm days in the summer".
State of the art would be quality passive solar design, Sips
construction with R 80 ceiling, Insulated foundation and under basement
floor. Tri pane glass LowEargon, high solar heat gain glass SHG, with
proper sun in summer permanent awnings, even an insulating foam core
auto exterior closing shutter panel system. Insulated curtains with
cellular shadees in tracks. Window R value closed could be R 40.
A combination of heat sources depending on what you could afford ,
Solar- wind powered, Geothermal heat pump radiant floor heat with AC and
Ng or propane backup Heating costs could on a pay basis be 1/20 th of
normal houses, a key point in keeping expensive costing heat and energy
options down. AC you would have forced air so Ac additional is cheap, A
VS DC blower would run on humidistat for days when humidity removal is
only important. Its all standard equipment, just pick it right.
Less could work, esp since insulation works 5% better per 1000' of elevation.
Maybe not, since warm air rises.
That's 20-year-old "mass and glass," vs the state of the art! :-)
Expensive and hard to seal at the edges. Better to circulate warm air
between the living space and a low-thermal-mass sunspace with lots of
south glazing during the day and let the sunspace get cold at night.
Cooling and dehumidification are unlikely needs at that altitude.
NREL says 660 Btu/ft^2 falls on the ground and 1240 falls on a south wall
on an average 20.6 F December day with a 34.9 high in Eagle, CO at 6513'.
The average temp in July is 66.6, with an 86.0 daily high and a 47.2 low
and humidity ratio w = 0.0079 (very dry.)
A 40'x60'x8' tall house with 192 ft^2 of R4 windows and R48 (12" SIP)
walls and ceiling and 0.2 ACH would have 192/4 = 48 Btu/h-F of window
conductance + 1408/4829 = 29 for walls + 2400/48 = 50 for the ceiling
plus about 0.2x40x60x8/60 = 64 for 64 cfm of air leakage, totaling 191.
With 600 kWh/mo (2843 Btu/h) of indoor electrical use, it would only
need (65-20.6)191-2843 = 5637 Btu/h of heat, ie 135K Btu/day or 676K
for 5 cloudy days in a row. Solar gain through the windows is gravy.
A $1 square foot of R1 polycarbonate solar siding or sunspace glazing
with 90% solar transmission might gain 0.9x1240 = 1116 Btu/day and lose
6h(120-27)1ft^2/R1 = 558, for a net gain of 558 Btu/day, so we could heat
the house with 135K/558 = 242 ft^2 of glazing, eg an 8'x30' wall.
We could store heat for 5 cloudy days in a row in P pounds of water
cooling from 120 to 80 F, where 676K = (120-80)P, so P = 16900 lb,
eg 263 ft^3 in a 2' deep x 13' diameter welded-wire fence tank with
a plastic film liner, which might also contain a $60 1"x300' PE pipe
coil to make hot water for showers.
Well, it seems stupid to me, but I am not the one building the house.
I would say that 95% of the houses in this area don't have A/C. Claim
it isn't necessary. This is high mountain country in the middle of
passive solar for sure.. smart design (southfacing windows) and proper
insulation will cover most of your daytime/sunlight heating. a
properly designed house at that altitute may not need airconditioning,
either, with cooling fans, porches, etc.
take a look at ideas here:
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