Which insulation brand is best?

There is no single best insulation brand for every application, because the best brand depends on whether you need batts, blown-in, spray foam, or rigid foam. For fiberglass batts, the two leaders are Owens Corning Pink and Johns Manville, with CertainTeed close behind. Owens Corning is widely considered the premium brand due to its consistent quality, softer Pink Next Gen fibers that are less itchy, and excellent availability at Home Depot and Lowe's. Johns Manville is often preferred by contractors because it is slightly less expensive and offers formaldehyde-free binders. For blown-in fiberglass or cellulose, GreenFiber for cellulose and Knauf EcoBatt for blown fiberglass are top rated for low dust and high coverage. For closed-cell spray foam, Closed-cell leaders are Huntsman Building Solutions with Heatlok and Lapolla, and Carlisle with SealTite, both known for high R-value around R7 per inch and excellent air sealing. For open-cell spray foam, Icynene and Demilec are contractor favorites. For rigid foam board, Owens Corning FOAMULAR for XPS and Rmax or GAF for polyiso are considered best. If you want the most eco-friendly option, Rockwool or Roxul mineral wool is best for fire resistance, soundproofing, and moisture resistance. Overall, Owens Corning wins for brand recognition and warranty, but Johns Manville and Rockwool often win for value and performance.