Commonly Asked Insulating Questions and Answers
Q: Does R-value refer to inches?
A: No. R-value refers to insulation’s resistance to heat flow, not its thickness. Tiny air pockets trapped in the insulating material resist the passage of heat. The higher the insulation R-value, the greater it’s insulating power. R-value is usually determined by the thickness and the density of the insulation.
Q: What is a vapor retarder?
A: Vapor retarders help control the amount of moisture passing through insulation and collecting inside exterior walls, ceilings and the floors. There are three types of vapor retarders: Kraft faced (Kraft paper attached to insulation with a thin coat of asphalt); Foil faced (Foil-backed paper attached with a thin coat of asphalt); and Polyethylene (A separate 4-6 ml polyethylene film applied over installed insulation.)
Q: Does the vapor retarder on insulation affect the R-value?
A: No. There is virtually no thermal performance difference between unfaced FIBERGLASS insulation and Kraft-faced or foil-faced FIBERGLASS insulation when properly installed. Faced insulation contains a built-in retarder.
Q: Why does CODE pass spray foam insulation at a lower R-Value than blown or rolled out insulation
Great question! R-Value isnt the only measurer of how well your home is insulated. For example would you be warmer outside on a 50 degree day with a slight breeze in a wool sweater or a light windbreaker? The windbreaker!
What if there was no breeze….then the wool sweater would be great. Builders realize that wind effects your home and air leaks like a wool sweater are greatly diminish insulating performance. In my professional opinion Spray Foam will be used in every new home as it is the best insulator AND SEALER. The majority of builders foam their home 100% (because it pays for itself the first day in lower energy bill as apposed to the cost of the spray foam upgrade over a 30 year mortgage). Spray foam is now 3% of the insulating marketplace and is gaining FAST.
If you pay $37 more per month on a $7000 foam upgrade and saved $100 a month in your energy bill as it is cut in half…isn’t that a good investment? Yes. But more people now see spending the $7000 on on upgrading the kitchen instead of their insulation. When they can do both and spend less. Spray foam is one of the few upgrades that pays for themselves the first day!