Using the right materials to insulate a building can reduce your energy bills by as much as 50%. There are lots of insulating materials available, giving homeowners and builders lots of choice for optimising interior comfort, reducing bills and even cutting the risks and severity of fires.
To help you to decide which insulation material is best for your home, we’ve got a quick guide to the five most efficient options, including their R-values (the measure of their thermal resistance).
Fibreglass
Fibreglass is the most widely used insulating material these days. Also known as glass wool, fibreglass is made by melting recycled glass, soda ash, limestone and various other elements together until they become molten. Once molten, the mixture can be spun into thin fibres which can be woven into different shapes and thicknesses.
Fibreglass has an R-value of between 2.9 and 3.8 (the higher the R-value the better) and is useful because it doesn’t wick water or catch fire. This makes it safe for domestic, commercial and industrial buildings and fibreglass works well in smaller areas such as attics and basements.
Cellulose
Cellulose is made from recycled paper products and isn’t just an efficient insulator, it’s very environmentally friendly. The cellulose is broken down into tiny fragments before being turned into a fibrous product that can be blown into small spaces in buildings. You can use cellulose insulation in existing walls and ceilings, not just new builds.
Cellulose doesn’t trap air and so it’s also great at preventing the spread of fire, and with an R-value of 3.1 to 3.7, it’s more efficient than fibreglass.
Mineral wool
Mineral wool forms the basis of two types of insulation. There’s rock wool, which is a synthetic textile made from various natural elements and then there’s slag wool, which is made from the slag waste product from steel mills.
Around 75% of the mineral wool available is made from recycled materials and it’s fireproof. You’ll often find it in blanket insulation and loose-fill, where it offers an R-value of between 2.8 and 3.5.
Polyurethane
Polyurethane is great for filling small cracks and air spaces in buildings. The material is made by mixing various chemicals to make a foam, which is then applied with a spray gun. It’s got an R-value of between 3.8 and 6.3, but polyurethane is more expensive to install than fibreglass and cellulose.
Polystyrene
Polystyrene is a thermoplastic foam which offers great insulation against both heat and noise. It comes in two forms, expanded (EPS) and extruded (XEPS). EPS has an R-value of 4, while XEPS has an R-value of 5.5.
The smooth surface of polystyrene makes it popular in both domestic and commercial settings, but it is rigid, so the foam comes as sheets or blocks that are fitted into walls.
To sum up
Insulation materials are especially important now, with many of us looking to reduce our energy usage. There are several things you need to think about when you’re deciding which one to choose for your build. The materials with the higher R-values are best in areas like ceiling and roofs, where most of a home’s heat escapes from, whereas for walls and crawl spaces, the more medium R-values will work fine.
