If you've ever sat barefoot on a kitchen floor in July and felt the chill come up through it, that's heat moving the wrong way. Without underfloor insulation, your floor surface in winter sits at around 10–13 °C regardless of how warm the air is. Add a basic R1.4 underlay and the floor surface jumps to 16–18 °C — instantly more comfortable.
For most NZ timber-floor villas and bungalows, underfloor insulation:
- Costs $1,800–$3,200 unsubsidised, or ~$200 after the Warmer Kiwi Homes grant (90% co-funded for pre-2008 owner-occupied homes)
- Saves $250–$450 per year on heating
- Pays back in under a year for grant-eligible households
The catch: your home needs decent crawl-space access and clearance. A registered installer will do a free check.