Approximately half of all New Zealand houses have no wall insulation*. This results in space heating energy being wasted, makes these houses difficult to heat to healthy and comfortable temperatures and contributes to mould-problems with associated health impacts on occupants.

In houses that have ceiling and under-floor insulation and draught-proofing retrofitted already (for example through the government-funded Warm Up New Zealand: Heat Smart programme) insulating external walls typically reduces heat loss by approximately 40%. This makes wall insulation the most effective next step in upgrading the thermal efficiency of such houses. Read more …