Unless damaged, it can last 80 to 100 years in most houses before it needs to be replaced. However, insulation can start falling from fiberglass batts after 15 to 20 years, so if insulation was installed in batts well over a decade ago, it might be time for an inspection or a home energy audit.

Insulation helps increase the energy efficiency of home by reducing the amount of heat that escapes from it in the winter (containing the heat and keeping the house warm) and keeping it from getting too warm in the summer months (retaining the cold air and keeping the interior comfortable).

While insulation is easiest to add to new construction, it is possible to add it to an existing room as well. Insulating a room costs on average $650 to $1,000, with the average homeowner spending around $825 on adding blown-in insulation to existing walls and ceiling in a 10'x10' room.

The most common types of materials used for loose-fill insulation include cellulose, fiberglass, and mineral (rock or slag) wool. All of these materials are produced using recycled waste materials. Cellulose is primarily made from recycled newsprint. Most fiberglass products contain 40% to 60% recycled glass.