Attic Insulation Rating

As a benchmark one inch of solid wood has an r value of 1.

Attic insulation rating.

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. Insulation with a higher r value will perform better than insulation with a lower rating. Blowing insulation into walls is best left to the pros because it involves drilling into stud spaces that may contain electrical. Insulation level are specified by r value.

Inspecting your attic insulation. Find your zone on the map and then use the chart to determine the level of insulation you need to properly insulate your attic walls floors and crawlspaces. 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. Handy homeowners can install blown in insulation in the attic.

Your attic should have a certain amount of insulation in it and the recommended level of insulation for your attic is dependent on where you live. The attic is the easiest place to add insulation to improve your comfort and the energy efficiency of your home. The table below shows what levels of insulation are cost effective for different climates and locations in the home. R value is a measure of insulation s ability to resist heat traveling through it.

Achieving greater r values in attics 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 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. R values vary based on the type thickness and density of the material being used.

Now that you ve air sealed your attic and basement check your attic insulation levels and add more if necessary. So it s time to pay close attention to what s happening up there. The most effective places to add insulation to older homes are exterior walls attics basements and crawl spaces. Along with knowing the r value of a particular insulation it is also important to calculate the r value of a total system.

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.