The Science of Experience



Insulating Homes Based on Climates

Posted by Emillie Lee

Apr 26, 2017 9:00:00 AM


When it comes to insulation, many people believe that the more you use, the better. However, this is not really the case. While too little insulation can contribute to a chilly, drafty home and the formation of ice dams, using more insulation than necessary is just a waste of money and won't keep your home any warmer. How much insulation you need is dependent on your climate. Here's a look at general recommendations for the 7 major climate zones, as designated by the US Department of Energy.

Zones 1 and 2 (Hot)

These zones include the hot climates in Florida, central to southern Texas, southern Arizona and southeast California. Hawaii is also in Zone 1. Here, the recommendations are as follows:

  • R-20 for walls
  • R-60 for attics or roofs
  • R-10 for above-ground foundation walls

Zones 3 and 4 (Moderate)

This includes the moderate climates throughout most of the southern states, including most of California and the western-most edge of Washington, and stretching north through most of Maine, Iowa and Pennsylvania.

  • R-30 for walls
  • R-60 for attics or roofs
  • R-10 for above-ground foundation walls

Zones 5-7 (Cold)

Zones 5-7 include all states north of Pennsylvania, as well as a band stretching west from Wisconsin along the northern border of the US and dipping down into northern Utah. Alaska is also in Zone 7.

  • R-40 for walls
  • R-60 for attics or roofs
  • R-20 for above-ground foundation walls

Keep in mind that if you use fiberglass insulation, achieving a high R-value of 40 in the walls may be difficult. Polyurethane spray foam insulation help achieve the recommended insulation levels, especially in cold climates, because it takes up less space. To learn more about polyurethane spray foam insulation, visit the NCFI Polyurethanes website.

Topics: Energy Efficiency, Spray Polyurethane, NCFI, climate