re: programable thermostat
18 dec 2005
> does the thermal mass inside the envelope have any effect overall?
sure. a house with little thermal mass and insulation and lots of air leaks
can cool more quickly and save more energy during a setback. a house with
6000 ft^2 of drywall and g = 200 btu/h-f (and a 2/3/6000/(1/500) = 0.06 biot
number, since abby cares about that) and rc = c/g = 50 hours would only cool
to 30+(70-30)e^(-8/50) = 64.1 f during an 8 hour setback on a 30 f night.
so living lightly (vs tearing out insulation :-) can lower the fuel bill.