Attic Insulation Rating

The most effective places to add insulation to older homes are exterior walls attics basements and crawl spaces.

Attic insulation rating.

Insulation materials run the gamut from bulky fiber materials such as fiberglass rock and slag wool cellulose and natural fibers to rigid foam boards to sleek foils. The r value per inch for different types of insulation varies depending on the. R values vary based on the type thickness and density of the material being used. Proper attic insulation is the best way to prevent heat loss in the winter and retain cool air in the summer.

The higher the r value the better the thermal performance of the insulation. Bulky materials resist conductive and to a lesser degree convective heat flow in a building cavity. Insulation with a higher r value will perform better than insulation with a lower rating. Rigid foam boards trap air or another gas to resist conductive heat flow.

Along with knowing the r value of a particular insulation it is also important to calculate the r value of a total system. While there are additional considerations such as venting and moisture problems to take into account when you insulate under floors the united states department of energy recommends an r 25 rating in cold climates and an r 11 in warmer parts of the country. So it s time to pay close attention to what s happening up there. Insulation level are specified by r value.

The table below shows what levels of insulation are cost effective for different climates and locations in the home. First things first you need to go up into your attic inspect the condition of the insulation and calculate the current level of insulation. In comparison an inch of blown fiberglass insulation has an r value of 3 1 3 4 and an inch of blown cellulose in an attic has an r value of 3 2 3 7. Now that you ve air sealed your attic and basement check your attic insulation levels and add more if necessary.

R value is a measure of insulation s ability to resist heat traveling through it. Blowing insulation into walls is best left to the pros because it involves drilling into stud spaces that may contain electrical. The attic is the easiest place to add insulation to improve your comfort and the energy efficiency of your home. Inspecting your attic insulation.

As a benchmark one inch of solid wood has an r value of 1. Achieving greater r values in attics the higher the r value the better the thermal performance of the insulation.