Many forms of insulation exist, from bulky materials that resist conductive and convective heat flow in a home to sleek foils that reflect radiant energy. The right choice depends on your climate, your R-value requirements, and whether you are insulating a new or existing home.
The most popular types of insulation are fiberglass batts, loose-fill, rigid foams and spray foam. Learn more about each form to decide what type works best for your home.
Fiberglass
Fiberglass insulation is one of the most common and affordable types of insulation in North America. It consists of tiny glass fibers and is available in blanket (batts or rolls) and loose-fill forms. It is a very versatile material that can be used in walls, attics and floors. It can be used in conjunction with vapor barriers to improve indoor air quality and reduce moisture issues.
Fiberglass is also a safe and cost-effective option for new construction, as well as for re-insulating existing homes. It is non-flammable and non-corrosive, and it does not settle over time. However, it is not as effective at repelling moisture as cellulose or hemp insulation. This may lead to mold and mildew issues in the future.
Fiberglass is also a popular choice for DIYers, as it is easy to install and can dramatically improve home energy efficiency. Its main drawbacks are health concerns and a high environmental footprint. Fortunately, there are many other eco-friendly insulation alternatives to fiberglass, such as mineral wool and spray foam. Hemp is also an excellent alternative to fiberglass.
Cellulose
Cellulose insulation is a form of blown-in home insulation. It can be used in enclosed existing walls, new walls and attics. It is also a green product. It uses recycled newspaper, cardboard and other paper products. It is treated with boric acid, borax and ammonium sulfate to meet governmental fire retardant requirements. It is considered more environmentally friendly than fiberglass or rock wool.
It is not as effective as fiberglass in extreme temperatures, but it can still improve the performance of your home. It can help lower your energy bills, especially if you live in an older house. It is also a good choice for retrofitting old houses because it can be easily installed around pipes, ducts and electrical wires.
However, cellulose is hygroscopic and can soak up liquid water. Undetected leaks can cause it to sag within framing cavities, reducing its thermal performance. It is also not pest-repellent, so it must be treated with chemicals to ward off rodents and bugs. These chemicals, while meeting governmental safety standards, can be corrosive to metal fasteners and pipes.
Polystyrene foam
Polystyrene foam insulation works on the same principle as other bulk insulation materials; trapping air inside the material helps to resist heat flow. EPS and XPS both contain millions of tiny air pockets in their structure. This makes them effective insulators and gives them excellent R-values.
Unlike other types of insulation, EPS is closed-cell and will not deplete its performance over the course of a lifetime (in contrast to polyiso board that will deteriorate after circa 30 years). The manufacturing process is environmentally friendly too. It does not use CFCs, HCFCs or HFCs.
EPS is easy to cut with a box knife or hand saw and doesn’t need to be scored first before cutting. However, it does burn and billow black smoke so if used in a situation where fire resistance is critical it should be treated as a flammable material. XPS is similar in appearance to EPS but it’s slightly more durable, stronger and far easier to cut than EPS. It also has a higher compressive strength which is ideal for use as a structural insulation in floor, foundation and plaza decks.
Polyurethane
Polyurethane is a versatile plastic material that can be made in a wide range of shapes and sizes, including foam and hard solids. It is a durable, flexible and lightweight insulation type that can be used in many different applications in homes and businesses. It is also resistant to water, grease and oil. It can be molded, cast, thermoformed or spray applied and is easy to work with.
Polyurethane has one of the highest initial R-values per inch of any insulation and it will retain its R-value long after installation. It is more expensive than expanded polystyrene insulation (EPS) because it requires a higher amount of isocyanates and polyols to produce the final product, as well as other ingredients to control the foaming process.
Rigid polyurethane insulation panels are moisture-resistant and can be installed in walls, floors, ceilings and roofs to improve energy efficiency. It can help reduce fossil fuel usage and CO2 emissions in buildings by reducing energy costs for heating and cooling. The durable properties of PU insulation also help to make buildings last longer, resulting in less maintenance and repair requirements over time.
Polyisocyanurate
Rigid foam insulation is available in three major forms – Polyisocyanurate (PIR), Expanded Polystyrene Foam or Styrofoam (EPS) and Extruded Polyurethane Foam or XPS. Though they are close relatives in chemical composition, each offers distinct advantages and benefits.
PIR is made by having isocyanate and polyol react with each other to create a thermoset plastic that’s heavily linked through ring-like structures. This gives it superior fire resistance compared to other insulation types, while keeping moisture, smoke and toxic gases out of the home. It is also more environmentally friendly than EPS or XPS as it contains more recycled materials and has lower toxicity levels.
This insulation is typically produced in bunstock form or in individually box poured pieces. It can be fabricated into different shapes, including sheet insulation and pipe shells that fit directly over nominal pipe size (NPS) pipes. Unlike EPS, it has a double layer of facers for improved moisture resistance and adhesion. A recent study of in-service aged EPS and PIR insulation samples confirmed that these insulations retained their thermal performance, even after 13 years.