Air sealing isn't necessary for attic insulation, but it's incredibly helpful since it can help you identify and patch any existing air leaks. Failing to find these leaks before adding insulation can render your insulation less effective, leading to higher energy bills and potentially costly repairs down the line.

Yes, they address underlying issues, providing long-term seals and energy savings you might need help to achieve.

The most affordable way to insulate behind unfinished walls is to install fiberglass batts or rolls. These total around $0.75 per linear foot, with the width matching the gaps between standard studs perfectly. However, it’s important to consider the R-value of your insulation and the climate in your area, as fiberglass insulation isn’t the best in terms of preventing heat transfer. Plus, the most affordable option may cost more on electricity bills over time. The most affordable way to insulate behind finished walls is to leave them up and use blown-in insulation to avoid drywall replacement.

Rigid foam board insulation is one of the safest insulation materials for basement walls. The panels offer a moisture barrier to prevent mold and mildew build-up. At the same time, this material is also fire-resistant, so you don’t have to worry as much about a fire breaking out as you would with spray foam insulation.