Oscar_Lives wrote:

Your assumptions are wrong.

Pray do explain further.

HVAC criminal Don Ocean wrote:

...a bit can be saved on heating costs with proper humidification.

ASHRAE 55 says a 48x48x8' house with R20 walls and ceiling would be
equally comfy at 69.4 F and 20% RH or 68 F and 50% RH. If it's very
tight, with 0.5 air changes per hour, would "proper" humidification
to 50% save energy?

G = 48'x48'/R20 + 48x4x8/R20 = 192 Btu/h-F, so dropping the room temp
from 69.4 to 68 F saves 1.4x192 = 269 Btu/h. At 69.4 F and 20% RH, Pd
= 0.2e^(17.863-9621/(460+69.4)) = 0.1466, approximately, with wd
= 0.62198/(29.921/0.1466-1) = 0.003063. Air at 68 F and 50% RH has wh
= 0.007347. With 0.5x48x48x8/60 = 154 cfm of air leakage, humidifying
from wd to wh requires evaporating 154x60x0.075(wh-wd) = 2.96 pounds of
water per hour, which requires about 1000x2.96 = 2960 Btu/h of energy,
so the net "savings" is 2960-269 = -2691 Btu/h, or minus 64.6K Btu/day,
costing about $1/day more with oil heat or $2 per day with electric heat.

I've done these calcs several times now. HVAC people tend to forget that
evaporating water takes heat energy, even if a humidifier belt uses little
energy by itself, and that heat energy has to come from somewhere. And we
often get into discussions about health and furniture, vs energy and
forget that caulking a house (vs humidification) can raise the indoor RH
while SAVING on fuel bills.

Nick