Your insulation value is R-30. If you increase it to R-38, how much money might you save in a year?

Question

I have no idea how much better R-8 is, and how much it would save you. I guess it's generic. This is (for some strange reason) for math class. Could anyone help? Thanks in advance.

Answer 1

R-values are used to measure thermal resistance (insulation). Since this is almost certainly using SI units, R is measured in units of K * m^2/W. To find out heat loss, take the inverse (U), so that U = W/K*m^2. i.e. 1 watt of energy lost per square meter, per 1 degree temperature differential.

R-30 would mean that 1/30th of a watt would be lost per square meter, per degree difference. R-38 means you're losing 1/38th of a watt. By upgrading to R-38, you lose 21.1% less heat (1 - 30/38) to the outside, thus, your heating costs would be reduced by about 21%.