Insulation and Weatherization

Tips for Staying Comfortable

  • Caulk and weather-strip doors and windows that leak air.
  • Seal air leaks between your living space and your attic and/or crawl space. Leaks are common around plumbing and vents, heating ducts, light fixtures and wires. Be sure fixtures and wires are designed for direct insulation contact.
  • Install wall plate insulation gaskets behind outlet and switch plates on exterior walls (turn off the power before installing gaskets).
  • Install a 6-mil vapor barrier between your living space and your crawl space to prevent moisture from entering your home. The barrier should be installed on the ground, stretched from wall-to-wall and covering all exposed dirt.
  • Make sure your attic and crawl space have adequate ventilation to vent out moisture and summer heat.


  • The effectiveness of insulation is noted as an R-value, a measure of the material’s resistance to heat transfer. Higher R-values provide greater insulating value. R-values are additive – the more you add, the higher the R-value will be.
  • Use a ruler to check the existing insulation levels in your attic, ceilings, exterior walls, floors and crawl spaces.
Cellulose Blown-in Fiberglass Fiberglass Batting
Inches R-Value Inches R-Value Inches R-Value
5.29 R-19 8.0 R-19 6.00 R-19
8.36 R-30 12.25 R-30 9.75 R-30
10.59 R-38 15.5 R-38 12.26 R-38
12.26 R-44 17.7 R-44 14.25 R-44
13.37 R-49 19.50 R-49 15.5 R-49
  • Add new insulation to the existing insulation to increase the R-value using the following guidelines:
House Area Standard Enhanced
Attic/Ceiling R-38 R-50
Floor (over unconditioned space) R-30 R-38+
Wall R-20 R-22+
  • Use higher density insulation that has a higher R-value per inch of insulation in cathedral ceilings and in exterior walls.