Insulation is one of the best investments you can make in your home, but the choices can be confusing. Each type has strengths, weaknesses, and ideal applications. Here is a plain-language guide to the main options.
Fiberglass The most common and affordable option, fiberglass comes in rolls (batts) or as loose fill blown into spaces. It is widely available, easy to install in open walls and attics, and budget-friendly.
Best for: attics, open wall cavities, and budget-conscious projects. Watch out for: it must be installed without gaps to perform well, and it can lose effectiveness if it gets wet.
Spray foam Spray foam expands to fill every gap and crack, creating an excellent air seal as well as insulation. Closed-cell foam offers the highest insulating value per inch and adds rigidity.
Best for: sealing irregular spaces, rim joists, and crawl spaces, and for homes where air leakage is a major problem. Watch out for: it is the most expensive option and should be professionally installed.
Cellulose Made largely from recycled paper treated for fire resistance, cellulose is blown in as loose fill. It is eco-friendly, fills cavities densely, and performs well.
Best for: attics and retrofitting existing walls without tearing them open. Watch out for: it can settle over time and is sensitive to moisture.
Rigid foam board Stiff panels of foam provide high insulating value in a thin profile and resist moisture well.
Best for: basement walls, exterior sheathing, and tight spaces where thickness is limited.
Mineral wool Dense and fire-resistant, mineral wool also provides excellent soundproofing and resists moisture better than fiberglass.
Best for: areas where fire resistance and sound dampening matter, like interior walls.