Several types of insulation are effective for crawl spaces, with spray foam and rigid foam boards being two of the best options. Closed-cell spray foam insulation is a strong choice because it effectively repels moisture, resists biological growth, seals the air, and provides excellent thermal protection, especially in hard-to-reach areas. Rigid foam insulation boards are another excellent material as they insulate well, resist water damage, and will not settle over time like fiberglass or cellulose.

In addition to adding insulation to your attic, you may want to add a radiant barrier. A radiant barrier works by using reflective material, such as foil, on the attic floor. As heat penetrates the roof and enters the attic, the radiant barrier reflects the heat upward and back through the roof. If you receive a lot of direct sunlight on the roof, using both a radiant barrier and insulation in your attic can provide significant benefits.

We do not recommend fiberglass insulation for soundproofing purposes, especially if you are working on a room that’s part of your living space. Fiberglass insulation is dangerous, and the installation process is hazardous. It is also harmful to the environment. When there are so many newer, healthier non-fiberglass alternatives in the market, the lower cost of fiberglass insulation simply doesn’t justify the harm and danger it poses.

Insulating a detached garage won't reduce your home's heating or cooling bills—and insulating an attached garage will only have a small effect on your home's energy efficiency. However, insulating an attached garage can reduce the transfer of heating and cooling to and from the outdoors, which can reduce the amount of energy your home needs to stay comfortable. Also, having an insulated garage is just more pleasant. Balance the cost of insulating your garage with how you'll use the space to determine if the project is worth it.