DeAnna writes from Kokomo, Indiana: "I am in the process of building a house. Our builder has given us the choice of upgrading the insulation from R13 to R19. Our house is a one story house with a full walkout basement. The basement walls are 2X6 walls and the main level is 2X4 walls. I'm being told by a relative that you are not supposed to put R19 in 2X4 walls, because it gets too compressed for any R-value benefit. Please help clarify this for me. I don't want to pay for something I don't need or won't benefit me."

Answer:Fiber glass insulation works on the principle of trapped air pockets. By compressing fiber glass insulation, you decrease the amount of air trapped in the material. For example, compressing R-19 into a 2x4 wall will give you an R-13 value. It would be better to buy the product that best fits in the space. R-13 or R-15 batts are the best products for a 2x4 wall.