Insulation R-Values

The higher the R-Value the greater the insulating power

Insulation R-Values

What does that mean to you

The effectiveness of Insulation materials is measured by their thermal resistance, called R-value. For example, on fiberglass batts there will be a rating like R-13. This means the product has a total thermal resistance of 13. For comparison, the same thickness of wood would have an R-value of approximately 4.0. A plain window typically has an R-value between 1 and 2. An R-value of R-0 would indicate no thermal resistance at all, like an open doorway. When the door is open there is nothing resisting the heat from passing through. Every wall in a house has an R-value that is different based on the thickness of the walls and the number of doors and windows that are installed.

Tubes of insulation showing their R-Value

Tubes of insulation showing their R-Value.

Insulation R-Value by Zone

Find the Zone for the Area you Live in

United States map with zones for insulation

United States map with zones for insulation.

R-Values for New Wood-Framed Homes

Zones for insulating new houses

Zones for Insulating New Homes.

R-Values for Existing Wood-Framed Homes

Zones for insulating existing houses

Zones for insulating existing houses.

Wall Insulation: Whenever exterior siding is removed on an-

    Uninsulated Wood-Frame Wall:
  • Drill holes in the sheathing and blow insulation into the empty wall cavity before installing the new siding.
  • Zones 3 - 4: Add R-5 insulative wall sheathing beneath the new siding.
  • Zones 5 - 7: Add R-5 to R-6 insulative wall sheathing beneath the new siding.
  • Insulated Wood-Frame Wall:
  • Zones 4 - 7: Add R-5 insulative sheathing before installing the new siding.