Healthy Homes heating calculator: will your heaters pass?
This Healthy Homes heating calculator checks whether the heaters in your main living room meet the heating standard. Enter the room's required heating capacity and your heaters, and it applies the 1.5 kW, 2.4 kW, older heating and top up rules for you.
Rules checked against Tenancy Services on 23 October 2026. Nothing you type leaves your browser.
Get the required capacity.
The capacity your room needs comes from the government's formula. Tenancy Services' free tool works it out in about ten minutes.
Open the Heating Assessment Tool
Have these ready: the living room's floor area and wall heights (include any open plan space joined to it), which walls, floor and ceiling face outside, the size of each window, glass door and skylight with its frame, and how much of the floor and ceiling is insulated.
Check your heaters.
What counts as heating.
These are the heating standard's rules, from Tenancy Services' heating page, updated 25 September 2025.
- Heaters must be fixed, not portable, and each at least 1.5 kW
- Together they must reach the required heating capacity, so the room can be kept at 18°C
- Heat pumps and electric heaters need a thermostat
- Open fires and unflued heaters, such as portable LPG bottle heaters, never count
- If the required capacity is over 2.4 kW, an electric heater other than a heat pump does not count
- Older heating installed before 1 July 2019 can stay if each heater is above 2.4 kW, none is an electric heater (heat pumps are fine), and together they give at least 80% of what is needed
- If older heating falls short, a fixed electric heater with a thermostat can top it up, as long as the top up needed is 2.4 kW or less
- When an older heater wears out, its replacement must meet the full required capacity
How the required capacity is worked out.
The formula adds up how much heat the living room loses on a cold night, plus a set allowance for each square metre of floor.
It counts the heat lost through each ceiling, wall, floor, window and skylight, based on its size and how well it is insulated, plus the heat lost as the air changes once an hour. Ceilings, walls and floors that face a space outside the insulated part of the building, such as a garage, count at half. It then adds 40 watts for each square metre of floor. The target is 18°C inside, against a fixed cold outside temperature for each council area.
| Council area | Assumed outside temperature |
|---|---|
| Hamilton City | −3°C |
| Waipā (Cambridge, Te Awamutu) | −3°C |
| Waikato District (Ngāruawāhia, Huntly, Raglan) | −2°C |
| Matamata Piako | −3°C |
| Ōtorohanga | −3°C |
| South Waikato | −3°C |
| Waitomo | −3°C |
| Hauraki | −2°C |
| Thames Coromandel | −1°C |
| Taupō | −5°C |
| Auckland | 1°C |
| Tauranga | 0°C |
Source: Residential Tenancies (Healthy Homes Standards) Regulations 2019, Schedule 2, read on legislation.govt.nz on 23 October 2026. Homes built to the 2008 building code, and some apartments, use a second formula that generally allows smaller heaters; the Heating Assessment Tool picks the right one from your answers.
Heating questions landlords ask.
Use Tenancy Services' free Heating Assessment Tool. It asks for the room's size, wall heights, windows, which walls, floors and ceilings face outside, and the insulation, then gives the capacity in kW, rounded up to one decimal place. It is built on the formula in Schedule 2 of the Healthy Homes regulations. A qualified specialist can also work it out.
The heaters must be able to keep the main living room at 18°C. The formula assumes a cold winter outside temperature for each council area, for example −3°C in Hamilton and Waipā.
Only a fixed one with a thermostat, and only if the required capacity is 2.4 kW or less. Above 2.4 kW, an electric heater other than a heat pump does not count, except as a top up of 2.4 kW or less to heating installed before 1 July 2019.
Yes, if each older heater is above 2.4 kW, none is an electric heater (heat pumps are fine), and together they give at least 80% of the required capacity. When it wears out, the replacement must meet the full required capacity.
The required heating capacity, how you worked it out, and the type and kW of each heater. If you rely on older heating or a top up, say so. Our compliance statement tool lays this out for you.
No. Heaters must be fixed. Open fires and unflued heaters, such as portable LPG bottle heaters, never count.
Related tools and guides.
- Healthy Homes compliance statement toolFill in your statement and print it, free.
- Healthy Homes standardsAll five standards with the exact numbers.
- Healthy Homes assessment in HamiltonWhat an assessor checks, and what it costs.
- Property management in HamiltonHealthy Homes handled for the homes we manage.
Sources: Tenancy Services, heating standard, updated 25 September 2025; Tenancy Services, calculating heating capacity; Heating Assessment Tool guide; Healthy Homes Standards Regulations 2019. All read on 23 October 2026. This tool applies the published rules to what you enter. It does not inspect your home, and an exemption or a specialist's assessment can change the answer.
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