Fibreglass insulation vs foam insulation
Fibreglass insulationFibreglass insulation, also known as glasswool insulation, is made from glass that is melted down and spun into long fibres. It’s a type of bulk insulation that works by trapping thousands of tiny air pockets between the fibres. These air pockets break up the flow of heat, slowing down heat transfer. Fibreglass insulation is used all over the world as a reliable and high performing thermal insulation. It’s most commonly sold as rolls or batt insulation, and comes in a range of thicknesses depending on the R Value you need. Fibreglass or glasswool also has excellent sound proofing properties. For projects where reducing sound transfer is a priority, you can use specialised acoustic insulation batts. Find out more: How does fibreglass insulation work?
Foam insulationFoam insulation is typically made from polystyrene or polyisocyanurate, and can have an open-cell or closed-cell structure. The most common closed-cell foam insulation products are made from extruded polystyrene (XPS) or expanded polystyrene (EPS). Foam insulation products are generally quite thin for the R Value they can achieve. They typically have high compressive strength and excellent resistance to moisture. Foam insulation is commonly sold as rigid panels, boards or rolls of flexible wrap. Some products combine a foam core with reflective foil facing which helps manage radiant heat. Foam boards are not the same as spray foam or expanding foam insulation. Check out our guide to expanding foam vs insulation batts for more information.
Which is better foam insulation or fibreglass insulation?Both foam insulation and fibreglass insulation are highly versatile and reliable insulation materials. They are both suitable for residential use in hot, cold and temperate climate zones across Australia. Overall, neither is better than the other. However, one might be a better choice for your project, depending on the particular application and what you’re wanting to achieve. Below we compare fibreglass vs foam across a number of different categories.
Performance / R-ValueBoth fibreglass and foam are high performing insulation products that will improve energy efficiency and indoor comfort. Foam products can typically achieve a higher R-Value for a given thickness. Fibreglass insulation is available in a wide range of R-Values from R1.5 to R7.0.
CostFibreglass batts tend to be cheaper per m2 compared to foam insulation. On average, fibreglass batts cost $6-$10 per m2, while acoustic batts cost $10-$18 per m2. Foilboard rigid foam board insulation starts from $8 per m2, while reflective foam wall wrap starts from $12 per m2. More premium foam products such as Kingspan Kooltherm start from $26 per m2. Also read: How much does insulation cost per m2?
Handling and installationBoth foam and fibreglass products are easy to handle and suitable for DIY applications. They can be cut easily using a sharp utility knife and are safe to use, although we recommend wearing safety glasses, long sleeves and enclosed shoes for any DIY installation. Rigid foam insulation is non-toxic, non-itchy and contains no breathable fibres. In the past, fibreglass products have had a notorious reputation for being itchy to work with. However modern products like Knauf Earthwool insulation use special technology to reduce the itch factor to virtually nothing. An advantage of fibreglass batts is that they’re flexible and can be moulded around shapes and awkward gaps if needed.
LongevityThe foam and fibreglass products we sell at Pricewise Insulation are designed to last the lifetime of your house. We recommend checking the specific warranty of a product to compare longevity. Fibreglass products typically have a longer warranty than foam insulation. On average, our fibreglass insulation products come with manufacturer warranties over 50-70 years, while many of our foam products are backed by 10-25 year manufacturer warranties.
SustainabilityFoam insulation and fibreglass insulation will both help make your home more environmentally friendly by reducing heat loss and gain throughout the year. The higher the R-Value you insulate with, the greater the energy efficiency you can achieve. Fibreglass products are often made from over 80% recycled glass materials, and many of the fibreglass products we sell can be recycled. For more information about the sustainability of fibreglass vs foam, we recommend researching the particular companies that produce the products. Many companies have sustainability measures in place to reduce greenhouse gas emissions and cut down on waste. Also read: Environmentally friendly insulation options for Australian homes.
What type of insulation is best for my project?
Foam insulation applicationsFoam insulation is best suited to applications such as:
- Exterior wall sheathing
- Garage doors and floors
- Underneath floors, particularly floors with a radiant heating system
- Concrete slab insulation
- Around trenches and edge beams and in between pods
- Foilboard Insulation Green Rigid Panels
- Kingspan Air-Cell Insulation
- Trade Select by Ametalin
- Slabmate Underslab Insulation by Foilboard
- Expol Insulation
- Kingspan Kooltherm Insulation
- Pirmax Insulation
- Foamex Insulation
Fibreglass insulation applicationsFibreglass or glasswool batts are a good option for applications such as:
- Exterior and interior wall cavities
- Ceilings and attic spaces
- Under floors
- Between floors of a multi-storey house
- Soundproofing rooms
- Knauf Earthwool Insulation
- Bradford Soundscreen Acoustic Insulation Batts
- Bradford Gold Batts
- Fletcher Pink Batts