Most Efficient Insulation Materials

Insulating a building with the right materials can significantly reduce energy bills, and there are many options available to homeowners and builders to enhance interior comfort, lower bills, and minimize fire risks. To help you decide on the best under the floor insulation for your home, here’s a quick guide to the top five most efficient options and their corresponding R-values (a measure of thermal resistance).

1. Fiberglass:
   This is the most widely used insulation material today, made by melting recycled glass, soda ash, limestone, and other elements into thin fibers. Fiberglass has an R-value of 2.9 to 3.8, doesn’t absorb water or catch fire, and works well in smaller spaces like attics and basements.
2. Cellulose:
   Made from recycled paper, cellulose is environmentally friendly and efficient. Broken down into small fragments, it can be blown into small spaces in buildings, including existing walls and ceilings. Cellulose insulation doesn’t trap air and is effective in preventing the spread of fire, with an R-value of 3.1 to 3.7.
3. Mineral wool:
   Composed of rock wool and slag wool, mineral wool is made from recycled materials and is fireproof. It is available in blanket insulation and loose-fill, offering an R-value of 2.8 to 3.5.
4. Polyurethane:
   Ideal for filling small cracks and air spaces in buildings, polyurethane is made by combining chemicals to make a foam, which is then sprayed into place. It has an R-value of 3.8 to 6.3, but it’s more expensive to install than other options like fiberglass and cellulose.
5. Polystyrene:
   This thermoplastic foam offers excellent insulation against heat and noise and comes in expanded (EPS) and extruded (XEPS) forms. EPS has an R-value of 4, while XEPS has an R-value of 5.5, and its smooth surface makes it popular in both residential and commercial settings. However, polystyrene is rigid and comes in sheets or blocks, making it suitable for walls.

When choosing an insulation material, consider the R-value, with higher values being ideal for areas like ceilings and roofs, where most of a home’s heat escapes from. Medium R-values work well for walls and crawl spaces. Insulation materials are especially critical nowadays, with many people seeking to lower energy usage.