Healthy Homes insulation standard

Healthy Homes Standard 2 sets the insulation a rental has to have. Ceiling and underfloor insulation is required wherever it can reasonably be accessed and installed — so before you quote or start a retrofit, you need to know the R-value minimum for the property’s climate zone and whether the insulation already up there is good enough to leave.

What’s in and what’s out

The standard is about ceilings and subfloors, not walls.

• Ceiling and underfloor insulation is required wherever it can reasonably be accessed and installed.
• Walls are not a retrofit requirement — only new builds pick up wall insulation, through the Building Code.
• The minimum R-values depend on the property’s climate zone, and existing insulation can sometimes stay if it’s thick and sound enough.

Minimum R-values by zone

These apply to most rentals — those whose building consent was applied for before 3 November 2022. Homes consented after that date meet the newer, higher Building Code H1 standard and are treated as compliant. Zones follow the NZS 4218 three-zone map.

• Zone 1 & 2 (upper / central North Island — Northland, Auckland, Waikato, Bay of Plenty etc.): ceiling R2.9, underfloor R1.3.
• Zone 3 (lower North Island plus all of the South Island): ceiling R3.3, underfloor R1.3.

R-value is resistance to heat flow — higher means warmer and cheaper to heat. The South Island and lower North Island (Zone 3) lose more heat, so the ceiling minimum steps up to R3.3. Underfloor stays R1.3 nationwide.

When existing ceiling insulation can stay

Insulation installed before 1 July 2016 doesn’t have to be ripped out if it’s still doing its job. It qualifies if either of these is true:

• It’s at least 120 mm thick on average (a quick proxy for adequate ceiling R-value); or
• It met the R-value required when it was installed and hasn’t degraded by more than around 30% — not badly compressed, gapped, damp or damaged.

Any new or top-up insulation must be installed to NZS 4246:2016 (the safe-installation standard) — even coverage, no gaps around fittings, and correct clearances to downlights and flues.

Condition counts, not just R-value

Insulation that is damp, mouldy, compressed, or has gaps doesn’t comply even if the original R-value was fine. Check the whole ceiling cavity and subfloor, and record the product, R-value and install date for the compliance statement.

Technical amendments on 25 September 2025 tidied up inconsistencies in how the zones and R-values are expressed — the figures above are the current ones.