Cellulose insulation is one of the more efficient and cost effective varieties of insulation. However, when insulating an attic with cellulose it is essential to accurately determine how much you need.
When talking about insulation, R value refers to the material's resistance to heat and is measured per inch. The higher the R value the more powerful the insulation and the less of it you'll need. Recommended R values vary by region. Cellulose has an R value of slightly over 3.
To determine how much cellulose insulation you need, do a quick Internet search for the recommended R value in your location. Once you have this and the R value of cellulose — which is 3 — you have everything you need to calculate how much cellulose insulation you need. Simply take the R value required for your home and divide it by 3. The result is the number of inches of cellulose insulation your attic requires.