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buffalobillpatrick · 03-23-17, 04:14 PM

My windows & doors U=.25 = R-4

My walls 6" Polyiso foam is R-2 / inch @ 0*F and R-6 / inch @ 70*F
My wall average @ 0*F outside is about R-4 / inch = R-24

So my windows & doors loose heat about 6X faster per square foot, than my walls.

Conduction Heat Loss: Q = Area x U-value x Delta-T

Comes close for walls, windows, & doors, but ignores some BIG factors such as infiltration, wind washing, and Clear Cold Night Radiation.

http://www.healthyheating.com/Radian...m#.WNRBVvkrKUk

http://www.sensiblehouse.org/nrg_heatloss.htm

Radiant slab heat loss down & horizontal is very complex.
Depends on under slab & perimeter R-values, soil type, water content, soil temperature, outdoor temperature, slab temperature, room temperature, slab size, etc, etc.

03-23-17, 04:14 PM	#6
buffalobillpatrick Master EcoRenovator Join Date: Mar 2014 Location: Florissant, Colorado Posts: 599 Thanks: 814 Thanked 59 Times in 55 Posts	My windows & doors U=.25 = R-4 My walls 6" Polyiso foam is R-2 / inch @ 0F and R-6 / inch @ 70F My wall average @ 0F outside is about R-4 / inch = R-24 So my windows & doors loose heat about 6X faster per square foot, than my walls. Conduction Heat Loss: Q = Area x U-value x Delta-T Comes close for walls, windows, & doors, but ignores some BIG factors such as infiltration, wind washing, and Clear Cold Night Radiation. http://www.healthyheating.com/Radian...m#.WNRBVvkrKUk http://www.sensiblehouse.org/nrg_heatloss.htm Radiant slab heat loss down & horizontal is very complex. Depends on under slab & perimeter R-values, soil type, water content, soil temperature, outdoor temperature, slab temperature, room temperature, slab size, etc, etc. Last edited by buffalobillpatrick; 03-23-17 at 05:51 PM..*