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Heating makes up about a third of the energy bill in an average New Zealand home, according to EECA, the Energy Efficiency and Conservation Authority. A heat pump is the cheapest way to cover it. EECA puts heat pump running costs at around a third of heating with gas and about a quarter of bar and column heaters. What you actually pay comes down to three numbers, and you can work them out yourself.
How heat pump efficiency works
A heat pump moves heat from the outside air into your home rather than making it from scratch, so it puts out more energy than it uses. EECA says the average heat pump in New Zealand puts out three times more heat than the power it consumes.
That ratio has a name:
- COP (coefficient of performance) is heat delivered divided by electricity used. A COP of 3 means 1 kW of power gives 3 kW of heat.
- EER (energy efficiency ratio) is the same idea for cooling.
- ACOP and AEER are annual versions that include standby power.
EECA’s installation guide says an acceptable COP is at least 3, and better products may reach 4 or more. Consumer NZ also treats a COP or EER of 3 or more as good.
COP is not fixed. It drops as the outdoor temperature drops, and below about 7°C the outdoor unit can ice up and need to defrost, which uses extra energy. That is why each unit of heat costs more on a frosty morning than on a mild evening.
Looking for a heat pump? High wall sets from $859.99 incl. GST, delivered NZ wide. We arrange installation in Auckland, Hamilton, Tauranga, Rotorua, Wellington, Christchurch and Invercargill.
The heat pump running cost formula
Running cost = power input (kW) x hours of use x price per kWh
If you only know the heat output, divide it by the COP to get the power input. A heat pump delivering 5 kW of heat at a COP of 3.5 draws about 1.4 kW.
What price per kWh to use
The best number is the one on your own power bill. For a national benchmark, MBIE’s Quarterly Survey of Domestic Electricity Prices put the New Zealand average at 42.1 cents per kWh on 15/08/2026. That figure:
- includes GST and assumes prompt payment discounts are claimed
- models a household using around 8,000 kWh a year, about 22 kWh a day
- spreads fixed daily and lines charges across every unit used, so the per-kWh rate on your bill can be lower
MBIE notes the survey tracks advertised prices, not what households actually paid, and that prices vary by region and plan. The town and city figures in the same survey ran from 37.20c in Wellington City to 51.00c in Balclutha.
Worked example
EECA’s installation guide includes a sample performance chart for a heat pump rated at 6 kW. Here is what it would cost at full output, using MBIE’s 42.1c per kWh:
| Outdoor temperature | Heat out (kW) | Power in (kW) | COP | Cost per hour | Cost per kWh of heat |
|---|---|---|---|---|---|
| 7°C | 6.1 | 1.9 | 3.2 | 80c | 13.1c |
| 2°C | 5.2 | 1.75 | 3.0 | 74c | 14.2c |
| 0°C | 5.1 | 1.71 | 2.98 | 72c | 14.1c |
| -5°C | 4.32 | 1.54 | 2.8 | 65c | 15.0c |
Four hours on a 7°C evening at full output: 1.9 kW x 4 hours x $0.421 = $3.20. Run it that way for 90 winter evenings and the total is about $288.
Two points stand out. In the cold the heat pump draws a little less power but delivers a lot less heat, so each unit of heat costs more. And full output is the worst case. Inverter compressors slow down as the room nears the set temperature, and EECA says heat pumps use the most energy getting a room up to temperature. Once the room is warm, the hourly cost usually falls.
Using the energy label instead
The Energy Rating Label shows yearly energy use in kWh for heating and cooling. Consumer NZ’s method is simple: label kWh x your price per kWh. On the label, all of New Zealand sits in the cold zone. EECA’s Efficient Appliance Calculator lets you compare heat pumps sold here by efficiency and region. Consumer NZ says the calculator assumes 25c per kWh, so change it to your own rate.
EECA tips that cut running costs
- Set the temperature between 18°C and 21°C. Above 21°C uses more power. Below 18°C invites damp and mould.
- Do not run it all day and night. EECA calls that a myth. Run it when you are home and use the timer to warm the room before you get up or get back.
- Heat the room you use and close the doors to rooms you do not.
- Clean the removable filter once a month in winter with a vacuum or warm water. A clogged filter makes the heat pump use more power.
- Use Heat mode, not Auto. In Auto the unit can switch between heating and cooling as the room temperature moves, which wastes energy.
- Leave the fan on Auto. Low or Quiet in very cold weather cuts the heat output and the efficiency.
- Insulate, add thermal curtains and block draughts under doors so the heat pump does not have to work as hard.
- In summer, try fans or fan-only mode with windows open first. If you need air con, close doors and windows, cool one room and set it no lower than 24°C during the day. Dry mode uses less energy than full cooling.
- Check you are on the right power plan. MBIE points to Consumer’s Powerswitch site for comparing retailer prices in your area.
Sizing affects cost too. An undersized unit runs flat out more often, and EECA says its extra running costs generally outweigh the cost of the next size up. If your old heat pump struggles, compare current high wall heat pumps, with sets from $859.99, and check the heating kWh on each label.
NZ DEPOT offers installation within 15 km of Auckland, Wellington, Christchurch, Hamilton, Tauranga, Rotorua and Invercargill. Elsewhere, use your own licensed installer. Get a heat pump installation quote.
Frequently asked questions
How much does a heat pump cost to run per hour in NZ?
Using EECA’s sample 6 kW chart and MBIE’s 42.1c per kWh average, about 65c to 80c an hour at full output, depending on the outdoor temperature. Once the room reaches temperature the unit slows down and the cost usually drops. Use your own bill’s rate for a better figure.
Is it cheaper to leave a heat pump on all day?
No. EECA says running a heat pump constantly uses more energy overall. Run it when you are home and use the timer to warm the room shortly before you need it.
What temperature should I set my heat pump to?
For heating, EECA recommends 18°C to 21°C. For cooling, it suggests a minimum of 24°C during the day, because a lower setting will not cool the room any faster.
Is a heat pump cheaper to run than gas?
EECA estimates that for an average household, a heat pump costs $122 a year less to run than piped gas heating and $352 a year less than bottled LPG, before daily gas connection charges.
Does dry mode use less power than cooling?
Yes. EECA says the dehumidifying mode uses less energy than full air conditioning.
More heat pump guides
Sources
- EECA, Good practice guide: heat pump installation, March 2022 (COP, EER, sample performance chart, efficient use checklist)
- EECA, Heat pumps (efficiency and cost comparisons)
- EECA, Buy an efficient heater (share of energy bill, gas and LPG comparison, Efficient Appliance Calculator)
- EECA, Use your heat pump efficiently
- EECA, Heat and cool efficiently at home (cooling tips)
- MBIE, Electricity cost and price monitoring (QSDEP method, Powerswitch)
- MBIE, Quarterly Survey of Domestic Electricity Prices, report for 15/08/2026
- Consumer NZ, How to buy the best heat pump (updated May 2026)
- Consumer NZ, Zoned Energy Rating Label: what you need to know (updated May 2025)
Ready to choose a heat pump? High wall sets from $859.99 incl. GST, delivered NZ wide. We arrange installation in Auckland, Hamilton, Tauranga, Rotorua, Wellington, Christchurch and Invercargill.
