It happens every June. The first proper cold snap arrives, the heat pump goes on, and a few weeks later the power bill lands with a thud. If you have ever stared at that bill wondering whether your heat pump is the problem, this guide is for you. Below, we break down what a heat pump actually costs to run in New Zealand this winter, how it compares with other heaters, and the simple habits that keep costs down without sacrificing warmth.

The short answer

A typical heat pump costs roughly 12 to 18 cents per hour to run. Larger units heating big open-plan spaces cost more per hour, but a heat pump remains the cheapest form of electric heating available for New Zealand homes. For many households that works out to around $300 a year, far less than most would spend achieving the same warmth with portable electric heaters.

Running costs by heat pump size

With residential electricity averaging about 39 cents per kWh nationally in early 2026, here is what you can expect:

Heat pump size Typical use Approx. running cost per hour*
Small (approx. 3.5 kW) Bedroom or study 12 – 18 cents
Medium (approx. 6 kW) Living room or open-plan area 20 – 30 cents
Large / ducted (8 kW+) Whole home 35 – 60 cents+

*Estimates based on a national average electricity price of approximately 39c/kWh. Your rate, home insulation and thermostat setting will move these numbers up or down.

Why heat pumps are so much cheaper to run

A plug-in heater converts one unit of electricity into one unit of heat, and that is the best it can ever do. A heat pump does not generate heat at all. It transfers warmth from the outside air into your home, which is why modern units deliver three to four kilowatts of heat for every kilowatt of electricity they use. In industry terms this is the COP, or coefficient of performance, and it is the single biggest reason heat pumps outperform every other electric heater on running cost.

Heater type Heat delivered per kWh of power Approx. cost for 2 kW of warmth per hour*
Heat pump 3 – 4 kW 10 – 13 cents
Panel or fan heater 1 kW Around 78 cents
Oil column heater 1 kW Around 78 cents

*Approximate, at 39c/kWh. Heat pump efficiency drops a little on very cold mornings but remains well ahead of resistive heaters in Auckland conditions.

Put simply: for the same warmth, a panel heater can cost several times as much to run. Over a 100-day Auckland winter with five hours of evening heating a day, that difference adds up to hundreds of dollars.

What actually drives your winter heating bill

Two identical heat pumps in two different homes can produce very different power bills. The main variables:

  • Thermostat setting. Every degree above 21°C adds noticeably to running costs. The World Health Organization recommends 18°C as a minimum for healthy indoor temperatures; 19–21°C suits most living areas.
  • Insulation and draughts. A well-insulated home holds its heat, so the heat pump cycles down sooner. If your home leaks heat, no heater will be cheap to run.
  • Sizing. An undersized unit runs flat out constantly; a correctly sized one cruises. This is why a proper in-home assessment matters more than the sticker price.
  • Filter condition. A clogged filter forces the unit to work harder for less heat. Cleaning filters monthly in winter is the easiest saving available.
  • Your electricity plan. Rates vary widely between retailers and regions, and some plans offer cheaper off-peak power that suits timer use.

Five ways to cut your heat pump running costs this winter

  • Set it to 19–21°C and leave it. Cranking the thermostat to 28°C does not heat the room faster; it just keeps the unit working at maximum for longer.
  • Use Heat mode, not Auto. Auto mode can flick between heating and cooling as the room temperature fluctuates, wasting energy.
  • Heat the room you are in. Close doors to unused rooms so you are not paying to warm empty space.
  • Clean the filters monthly. Five minutes with a vacuum keeps efficiency up and power use down.
  • Book a pre-winter service. A professional heat pump service keeps the coils, refrigerant and outdoor unit performing the way the manufacturer intended, and catches small faults before they become expensive ones.

Is it cheaper to leave a heat pump on all day?

Generally, no. Heating an empty home costs more than reheating it when you return, because a house continuously loses heat to the outside air while the heat pump keeps topping it up. The smarter approach is to use the built-in timer so the unit switches on 15 to 30 minutes before you get home or wake up. The exception is poorly insulated homes in cold regions, where a low constant setting can occasionally work out similar, but for most Auckland homes the timer wins.

When an old heat pump is costing you money

Heat pump technology has improved significantly over the past decade. If your unit is 10 to 15 years old, struggles to keep the room warm, or ices up regularly, it may be costing you considerably more per hour than a modern high-efficiency replacement from Mitsubishi, Daikin or Panasonic. Rising power prices make the payback on an upgrade faster than most people expect. And if you bank with ASB, ANZ or BNZ, their better-homes lending offers let eligible customers top up their mortgage at low interest rates for heat pumps and ventilation, which spreads the cost of an upgrade over time.

Frequently asked questions

How much does it cost to run a heat pump per hour in NZ?

Roughly 12 to 18 cents per hour for a typical unit, and 20 to 30 cents for a larger 6 kW unit, at current average electricity prices.

What is the cheapest way to heat a house in NZ?

A heat pump. It produces three to four times more heat per dollar than plug-in electric heaters, making it the most efficient form of electric heating available.

What temperature should I set my heat pump to in winter?

Between 19°C and 21°C for living areas. Higher settings increase running costs without making the room heat up any faster.

Does servicing really reduce running costs?

Yes. Dirty filters and coils force the unit to draw more power for less heat. Regular cleaning and an annual professional service keep efficiency at its peak.

Keep your winter warm and your bills down

A well-chosen, well-maintained heat pump is the cheapest way to stay warm through a New Zealand winter. If yours is due a service, or you suspect an ageing unit is inflating your power bill, Air Conditioning Group can help, from a pre-winter tune-up to a free in-home assessment for a modern heat pump installation. Call us on 0800 224 123 or get a quote online.