- Annual cost
- <$200 to ~$1,000 2.5 kW to 10 kW+ (Consumer NZ)
- Average power price
- about 42c/kWh national average, May 2026
- Heat per kWh
- 3–5 kWh typical COP range in mild weather
- EECA setpoint advice
- 20–21°C max for heating
How much does it cost to run a heat pump in NZ?
For most homes, a heat pump costs a few hundred dollars a year. Consumer NZ puts annual running costs at under $200 for a small 2.5 kW unit and about $1,000 for a 10 kW or larger unit. Your figure depends on the unit size, how many hours you use it, how cold your winters are and what you pay per kWh.
Heat pumps are cheap to run because they move heat rather than make it. A unit with a coefficient of performance (COP) of 3 delivers 3 kWh of heat for every 1 kWh of electricity. Consumer NZ considers a heating COP of 3 or more good.
How do you calculate heat pump running costs?
Divide the heat output by the COP to get electricity use, then multiply by hours and your power price. The formula is: heat output (kW) ÷ COP × hours × price per kWh. A 5 kW unit at COP 3.5 draws about 1.43 kW, so an hour at 42c/kWh costs about 60c.
Two cautions. A heat pump rarely runs at full rated output for long; once the room is warm it throttles down, so real hourly costs are usually lower than the full-output figures below. And the price per kWh on your bill varies by region and plan. The national average was about 42c/kWh in MBIE's May 2026 survey, with main centres sitting a few cents either side. Check your own bill for the most accurate result.
What does each heat pump size cost per hour?
At 42c/kWh and full rated output, hourly costs range from about 30c for a 2.5 kW unit on a mild day to about $1.34 for an 8 kW unit on a cold night. The table shows two COP assumptions: 3.5 for mild conditions and 2.5 for a frosty night when efficiency drops.
| Unit size (heat output) | Power drawn at COP 3.5 | Cost/hour, mild (COP 3.5) | Power drawn at COP 2.5 | Cost/hour, cold (COP 2.5) |
|---|---|---|---|---|
| 2.5 kW | 0.71 kW | about 30c | 1.0 kW | about 42c |
| 3.5 kW | 1.0 kW | about 42c | 1.4 kW | about 59c |
| 5 kW | 1.43 kW | about 60c | 2.0 kW | about 84c |
| 6 kW | 1.71 kW | about 72c | 2.4 kW | about $1.01 |
| 8 kW | 2.29 kW | about 96c | 3.2 kW | about $1.34 |
Our estimates. Assumptions: unit running at its rated heating output for the full hour; COP 3.5 (mild) and 2.5 (cold) chosen to illustrate the range, not taken from any specific model; electricity at 42c/kWh, the national average reported for MBIE's May 2026 survey. Real use is usually below full output.
What might a heat pump cost over a winter?
A living-room heat pump used most winter evenings commonly costs $200–$500 over the season, depending on climate and hours. The examples below show how the same unit can cost twice as much in a cold, long winter as in a mild one.
| Scenario | Average heat output | COP | Hours/day | Days | Season cost |
|---|---|---|---|---|---|
| Mild climate, evenings only | 2.5 kW | 3.5 | 6 | 120 | about $220 |
| Mild climate, less efficient unit | 2.5 kW | 3.0 | 6 | 120 | about $250 |
| Cold climate, longer season | 3.0 kW | 3.0 | 8 | 150 | about $500 |
Our worked examples, rounded. They are estimates to show how hours, climate and COP change the bill, not a prediction for your home.
Why do heat pumps cost more to run in cold places?
Heat pumps work harder when there is less heat in the outside air. As temperatures approach zero, efficiency falls and the outdoor unit periodically defrosts itself, which uses energy without heating your room. Consumer NZ notes that extracting heat gets more difficult as the temperature drops.
A Queenstown, Invercargill or Christchurch home will usually run its heat pump for more hours and at a lower average COP than an Auckland or Tauranga home. That is why correct sizing matters more in the south: an undersized unit runs flat out on frosty nights. Our sizing guide and size calculator include a cold-climate adjustment. When comparing models, the Zoned Energy Rating Label treats all of New Zealand as the cold zone, and the Gen Less efficient appliance calculator lets you pick your region.
Is a heat pump cheaper to run than an electric heater?
Yes, much cheaper for the same heat. A plug-in electric heater turns 1 kWh of electricity into 1 kWh of heat, so at 42c/kWh heat costs 42c per kWh. A heat pump with a COP of 3 delivers the same kWh of heat for about 14c, and at COP 4 about 10.5c.
| Heater | Efficiency | Cost per kWh of heat |
|---|---|---|
| Plug-in electric heater (fan, oil column, panel) | 1 kWh heat per kWh | about 42c |
| Heat pump on a cold night | COP 2.5 | about 17c |
| Heat pump, typical winter day | COP 3 | about 14c |
| Efficient heat pump, mild weather | COP 4 | about 10.5c |
Our calculation using the national average price.
How can you reduce heat pump running costs?
Set the thermostat no higher than 20–21°C, heat only the rooms you use, and use a timer rather than leaving the unit on all day. EECA recommends a heating setpoint of 20°C or 21°C maximum, and warns against the auto mode, which can switch to heating or cooling when you do not expect it.
- Set 20–21°C, not 25°C. Higher setpoints do not warm the room faster; they just cost more once it gets there (EECA).
- Use timers. Warm rooms shortly before you use them and switch off when you do not.
- Close doors and curtains. Keep the heat in the room the unit is sized for.
- Clean the filters. Clogged filters reduce airflow and efficiency. See how to clean heat pump filters.
- Insulate first. Ceiling and underfloor insulation cut the heat your home needs. Eligible owners may get grants through Warmer Kiwi Homes.
- Check your power plan. Compare plans and off-peak rates; the price per kWh is half of the running cost equation.
- Buy on star rating. Higher-star models use less electricity for the same output. Consumer NZ lists ignoring the star rating as a common buying mistake.
More settings advice is in best heat pump settings for winter.
Frequently asked questions
How much does a heat pump cost to run per hour in NZ?
At about 42c/kWh, a 2.5 kW unit at full output costs roughly 30c–42c an hour and a 5 kW unit about 60c–84c, depending on outdoor temperature. Most of the time units run below full output, so real costs are usually lower.
How much does a heat pump add to a power bill each year?
Consumer NZ estimates under $200 a year for a small 2.5 kW unit and about $1,000 a year for a unit of 10 kW or more. Cold climates and long hours push costs up.
Is it cheaper to leave a heat pump on all day?
Generally no. Heating an empty home costs money. Use a timer to warm the room before you need it. In very cold places, a low setback temperature overnight can avoid long warm-up times, but setting it lower or off when out is usually cheaper.
What temperature should I set my heat pump to in winter?
EECA recommends a maximum of 20–21°C for heating. Each degree higher increases running costs.
Are heat pumps cheaper to run than wood burners or gas?
It depends on firewood, gas and power prices where you live. For a heat pump, work out the cost per kWh of heat with the table above (about 14c at COP 3 and 42c/kWh), then compare it with what you pay for the same heat from wood or gas.
Does using cooling in summer cost much?
Cooling a room usually costs less than winter heating because the temperature difference is smaller. EECA suggests setting cooling to at least 24°C during the day and using dehumidifying mode where it is enough.
Does a bigger heat pump cost more to run?
A bigger unit heating the same room does not necessarily use more power, but an oversized unit costs more to buy and can cycle on and off inefficiently. An undersized one runs flat out. Correct sizing gives the best result.
Sources
- Consumer NZ, Heat pumps buying guide
- MBIE, Electricity cost and price monitoring (Quarterly Survey of Domestic Electricity Prices)
- Powerbill.co.nz, Electricity price per kWh in NZ 2026 (summarising MBIE May 2026 survey)
- EECA / Gen Less, Guide to choosing a heat pump
- Consumer NZ, Zoned Energy Rating Label: what you need to know
- Consumer NZ, 5 common heat pump buying mistakes