Which Way Does the Foil Face on Insulation?

If you're wondering whether to put the foil side of foam insulation board shiny side in or out, consider whether you want to make the space inside warmer or cooler. If you want to make the space warmer, the foil should face inside so it can reflect radiant heat back into the room.

Which side of the insulation faces out?

Hi Kim, Regardless of whether fiberglass insulation is installed in a wall, attic, or crawlspace; the paper facing should always face toward the inside of the home. That's because the paper contains a layer of asphalt adhesive which prevents water vapor from passing through it.

Which way do you face foil?

Since aluminum foil has a shiny side and a dull side, many cooking resources say that when cooking foods wrapped or covered with aluminum foil, the shiny side should be down, facing the food, and the dull side up.