Which is better for a cold climate?

The Knauf R-38, because it packs more thermal resistance into each cavity. Pair it with a separate vapor retarder on the warm side.

Can I use the Owens Corning R-30 in 16-inch walls?

Not cleanly. It is 24 inches wide, so it will not friction-fit 16-inch stud bays and would need cutting, which wastes material and can leave gaps.

Does the facing on the Owens Corning batt matter?

Yes. The facing acts as a vapor retarder and must face the warm, interior side. In some assemblies a faced batt can trap moisture, so check your local code.

Is the higher R-value worth it?

R-38 cuts heat flow by roughly a quarter compared with R-30 in the same cavity. That matters most in cold climates and on ceilings.

Both are fiberglass batts and last decades if kept dry and undisturbed. Performance drops if they get wet or compressed.

Do both meet green building requirements?

Both are GREENGUARD certified, so both qualify for low-emission insulation specs.

Knauf R-38 Fiberglass Insulation Batt vs Owens Corning R-30 Faced Insulation Batt

Buy the Knauf R-38 for 16-inch stud bays and colder climates where the extra R-value matters. Buy the Owens Corning R-30 for 24-inch framing, or where you want a built-in vapor retarder from the facing. Prices were not provided for either product, so check current store prices on Deal.ai before ordering.

Ask our shopping agent

It checks today's price at every store, compares the alternatives and answers in about a minute.