The Healthy Homes heating standard, explained

Of the five Healthy Homes standards, heating is the one with the most moving parts and the most expensive way to get it wrong. The requirement itself is narrow: the main living room, one room, must have fixed heating that can bring it to a healthy temperature (the benchmark used is 18°C) on the coldest days where the property is. Everything else, which heater, what size, what counts, flows from that sentence.

One room, but properly

The standard deliberately targets the main living room rather than the whole house, the room where households actually spend their winter evenings. The heating must be fixed: a heat pump, a fixed electric heater, a wood or pellet burner, or certain other fixed devices. What does not count is just as important: portable plug-in heaters do not qualify, and neither do open fires. An unflued gas heater doesn't qualify either, it adds moisture to exactly the air you are trying to keep dry.

Capacity is calculated, not vibes

The required heating capacity depends on the room's size, its insulation, how much glazing it has, and the local climate. Colder parts of the country carry higher requirements for the same room: New Zealand's heating calculations use three climate bands, and a living room in Invercargill needs materially more capacity than the same room in Whangārei. The good news is nobody has to do this maths by hand, the official heating assessment tool at tenancy.govt.nz takes the room's details and the address and produces the required capacity in kilowatts.

• Run the official tool for the specific address, not a similar one nearby.
• Keep the tool's result with the property's records, it is compliance evidence in itself.
• If an existing heater's capacity roughly matches the requirement, check the tolerance rules on tenancy.govt.nz before assuming it passes.

The heater you inherited

Most compliance questions arrive with a heater already on the wall. The test is whether that device is fixed, qualifying, and big enough for the calculated requirement. A heat pump installed a decade ago for a different, smaller idea of the room is the classic case: qualifying type, insufficient capacity. Top-up rules exist for rooms that already have some qualifying heating, the details live with the official guidance.

Evidence worth keeping

The heating standard generates paperwork naturally, keep it. The heating assessment calculation, the installer's invoice showing make, model and capacity, and a photo of the installed unit and its rating plate together answer nearly every question a tenant, the Tenancy Tribunal, or a future buyer could ask. File them against the property, not in an email thread from three years ago.