I am starting to think about winter. (partly because it is so hot) I think I am going to add more insulation to my attic space. I currently have R-38 over most of it. But I only have R-19 over the master bedroom vaulted ceiling. I guess I have the code minimum at the time of installation.

Interesting find from askthebuilder.com

Loose fill blown fiberglass insulation has another slight problem. As the temperature difference between the living space and attic increases, the R-value of blown fiberglass diminishes. In extreme situations, such as the upper Midwest, this reduction in R-value approaches 50 percent.

This phenomena seems to occur as a result of thermal convection. The trapped air molecules in the insulation are pulled up through the insulation into the colder attic air. This problem has been successfully solved by installing fiberglass batt insulation over the top of loose fill or blown insulation.

I live in the Midwest and have blown fiberglass! But seriously, I don’t plan on adding more blown fiberglass. I either have to install batts or have someone else blow in more. I always  think about DIY first. So I think I will wait until one of the big box store has a sale on insulation.

Adding insulation will get you a 30% federal government tax credit. (USA) So I will be adding more insulation this fall.