Why heat pumps lead on efficiency
BRANZ puts it simply: heat pumps use electricity to move heat around, not to generate it. It calls them the most efficient form of purchased space heating commonly available, because apart from solar they're the only heating where you usually get more heat out than the energy you put in.
Consumer NZ says a good heat pump has a COP (coefficient of performance) of 3 or more, so 1 kW of electricity gives 3 kW of heat. A plug-in heater gives a touch under 1 kW of heat for every 1 kW it uses.
Two honest caveats. BRANZ says air-to-air heat pumps lose efficiency once it's colder than 6 to 7 degrees outside, though some models still heat at minus 15. And in a BRANZ study of 160 households with heat pumps, more people said their energy costs had gone up than down, and people kept their homes warmer than before.
Heat pump, burner or gas, side by side
| Heat pump | Wood or pellet burner | Flued gas heater | |
|---|---|---|---|
| BRANZ efficiency group | Best (COP above 1) | Average (COP below 1) | Average (COP below 1) |
| Building consent | Often not needed: Christchurch City Council says none for a heat pump | Needed for every new wood burner, BRANZ says | Christchurch City Council says none for a fixed gas heater |
| Who does the regulated part | A registered electrician connects it | Installed under that building consent | A gasfitter: homeowners can't install or alter gas appliances |
| Paperwork you should get | Certificate of Compliance and Electrical Safety Certificate | Council sign-off of the consented work | A gasfitting certificate within 20 working days of connection |
| Smoke and fumes | None | Smoke, which councils regulate | Fumes that must be flued outside |
| Cools in summer | Yes | No | No |
Wood burners and log burners
A wood burner is still common: EHINZ says 28.2% of dwellings used one as a main type of heating in 2023. It's also the heating with the most rules attached.
BRANZ says every new wood burner installation needs a building consent, and the national air quality standard requires a discharge of less than 1.5 grams of particulate per kilogram of dry wood and a thermal efficiency of at least 65%. Councils can go further: Environment Canterbury says low-emission wood burners can no longer be installed in five Clean Air Zones, Christchurch and Timaru among them.
BRANZ estimates home fires cause 29% of the national air pollution health burden. And EECA's Warmer Kiwi Homes programme stopped taking new wood and pellet burner applications on 9 January 2026.
Gas heating
A flued gas heater, one with a flue that carries the fumes outside, is gasfitting work. The PGDB says homeowners can't install, alter or repair a gas appliance, its gas pipes or its flue, and the gasfitter should give you a gasfitting certificate within 20 working days of connecting it.
Where you live matters. Te Waihanga says distributed natural gas is only available in the North Island, so in the South Island gas heating runs on bottled LPG. Our gas heating page has more.
Unflued gas heaters
BRANZ doesn't recommend any unflued gas heater, natural gas or LPG, for health and safety reasons: burning gas produces carbon monoxide and nitrogen dioxide, which need venting outside. An unflued gas heater can never count towards the healthy homes heating standard in a rental.
Electric heaters and central heating
Plug-in and panel heaters sit in BRANZ's middle group, with a COP of about 1: roughly all the electricity they use becomes heat, and no more. BRANZ says fixed heaters such as heat pumps and enclosed wood burners are more cost-effective to run than portable ones.
Hydronic heating (hot water central heating) runs warm water through underfloor pipes, radiators and towel rails. BRANZ says it can reach 70 to 90% efficiency depending on the system, responds slowly, and should come after good insulation. A BRANZ survey in 2015 found central heating in fewer than 5% of 560 houses.
A heat pump water heater is a different product: it heats your hot water, not your rooms, so check its rules separately.
Heating a rental
For landlords the choice narrows. Open fires and unflued gas heaters never count, and if the main living room needs more than 2.4 kW, electric heaters other than heat pumps don't qualify unless they're topping up qualifying heating installed before 1 July 2019. Our healthy homes heating guide has the detail.
What's yours to sort, and what isn't
You can
- List what heats each room now, and how old any burner is.
- Check if you're in a Clean Air Zone or airshed before replacing a burner.
- Keep a heat pump's filters clean and its outdoor unit clear.
Leave to a licensed installer
- Any gas appliance, gas pipe or flue: that's a gasfitter.
- A heat pump's refrigerant work and electrical connection.
- Installing or moving a wood burner, under a building consent.
What we'd do
What we'd weigh up
For most homes we'd put a heat pump first: it's the most efficient common heater, the paperwork is light, and it cools on the hot days. If you already have a wood burner you love, we'd keep it and add a heat pump for the rooms it can't reach, or ask a heat transfer system specialist whether moving that warmth around would do the job. We'd only consider gas where it's already piped to the house, and we'd steer clear of unflued gas heaters altogether.