Looking for the best attic insulation? That answer depends on your definition of “best.” The best performing way to insulate an attic doesn't always align with the most cost-effective way.

For example, fiberglass insulation is cost-effective but less airtight, while spray foam insulation ... Use fiberglass batts cut to fit snugly between studs. Add rigid foam boards on the backside ...

Foam board insulation is more expensive than traditional batt insulation ... For smaller pieces, seal them in with caulk or ...

It depends on your comfort level and the type of insulation you choose. Foam board and fiberglass batts are common methods ... tools and a bit of know-how. Spray foam, on the other hand, is ...