Question

I would really appreciate the help on this pass paper question.

Answer 1

Answer:

Heat lost thru doors & windows = (100 - 75 - 5) = 20

20% is the fraction of heat lost thru doors and windows

One wants to obtain the largest savings per unit of cost

roof:

200 / 600 = 1/3

150 / 1000 = .15

40 / 2300 = .017

The largest of these is 1/3 so the most benefit would be obtained by insulating the roof

Since heat loss thru the roof depends on heat loss thru the attic, this is the most cost effective in reducing heat loss

The more the difference in temperature between the ceiling and roof (attic) the more heat will be lost thru the roof, so insulating the roof will decrease the heat loss of the attic