When a US Department of Energy-funded laboratory looked into the difference between R-values (which measure insulation’s ability to trap heat) on the label versus in the walls, they found that even “perfectly installed” fibreglass insulation had R-values 11% lower than on the label (view study here). “Commonly installed” fibreglass insulation dropped to 20% lower than labelled.
With spray foam insulation, the R-value chosen will be the R-value of the house once completed and for the life of the building. While fibreglass’s performance reduces over time, spray foam doesn’t change.
So, what is the single most effective way to improve a home’s performance and save money on energy costs? Seal gaps to prevent heat loss from air movement.
This is why closed-cell polyurethane spray foam has one of the highest thermal resistance (R-Value by thickness) of any insulation product available globally. It fills cracks and seals drafts. It does not settle or sag and can be applied to awkward areas.
Closed-cell foam has been used in New Zealand as insulation in industrial applications since the 1970s and is growing in popularity as a residential product — as more discerning home-owners choose comfortable, high-performing homes.