Question

How many Btu per hour are lost through a 100-square foot wall that is made up of a 12-inch thick concrete block wall with an R value of 1.89 and 4 inches of fiberglass insulation with an R value of 14.8? The inside temperature is 65 degrees F and the outside temperature is 15 degrees F.

Answer 1

300 Btu per hour

Step-by-step explanation:

given data

area = 100-square foot

thick = 12 inch

R value at 12 = 1.89

R value at 4 = 14.8

inside temperature = 65 degrees F

outside temperature = 15 degrees F

to find out

How many Btu per hour

solution

we get here How many Btu per hour that is express as

Btu per hour =
`(area*temp\ difference)/(r\ value\ 12 + r\ value\ 4)` ............1

put here value we get

Btu per hour =
`(100(65-15))/(1.89+14.8)`

Btu per hour = 299.580

so Btu per hour is 300 Btu per hour