Insulation R-values: everything you need to know (2025)

R-value measures how well insulation resists heat flow—a higher value means better performance. The New Zealand building code sets minimum R-values to ensure homes are warm and energy-efficient.

These requirements vary across six climate zones, with different standards for roofs, walls, and floors. All new builds and extensions must meet or exceed these minimums.

While an upfront cost, investing in quality insulation can lead to significant long-term savings on your heating and cooling bills.