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.
United States map with zones for insulation.
Zones for Insulating New Homes.
Zones for insulating existing houses.
- 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.
- Zones 4 - 7: Add R-5 insulative sheathing before installing the new siding.