"How much does a heat pump cost to run?" is the question everyone asks after "how much does it cost to buy?" The answer is surprisingly low compared to other heating options - but only if the unit is correctly sized and used sensibly. Here are the real numbers for running a heat pump in New Zealand.
1. How heat pump efficiency works (COP explained simply)
A heat pump doesn't generate heat - it moves it. It extracts heat from the outdoor air and transfers it inside. This is why it's so much more efficient than any heater that burns fuel or converts electricity directly to heat.
The efficiency is measured by the COP - Coefficient of Performance. A COP of 4.0 means for every 1 kW of electricity the heat pump draws from the wall, it delivers 4 kW of heat into your room. That's 400% efficiency, which sounds impossible until you understand it's not creating energy - it's just moving it.
Typical COP ranges for residential heat pumps in NZ:
- Budget models: COP 3.2-3.8
- Mid-range models: COP 3.8-4.5
- Premium models: COP 4.5-5.2
There's a catch: COP drops as outdoor temperatures fall. That COP of 4.5 measured at 7 degrees might drop to 3.0 at minus 2 degrees. In the Waikato, winter lows are typically 2-6 degrees, so real-world winter COP is usually around 3.0-4.0 for most units.
2. NZ electricity rates in 2026
To calculate running costs, you need to know what you're paying for electricity. NZ residential rates in 2026 typically sit around:
- Standard rate: 28-35 cents per kWh (varies by region and retailer)
- Waikato average: around 30-33 cents per kWh
- Night rate (if applicable): 15-20 cents per kWh
- Daily fixed charge: $1.00-$2.00 per day (this applies regardless of heat pump use)
Check your latest power bill for your actual rate. We'll use 32 cents per kWh for the examples below, which is close to the Waikato average.
3. Real-world running cost examples
Here's what it actually costs to run different heat pumps in typical NZ conditions. We're using 32c/kWh and a real-world winter COP of 3.5 (a reasonable mid-range figure for a Waikato winter).
| Scenario | Electricity drawn | Cost per hour | Cost per day (8 hrs) |
|---|---|---|---|
| 2.5 kW unit (bedroom) | ~0.7 kWh | ~23c | ~$1.80 |
| 3.5 kW unit (large bedroom) | ~1.0 kWh | ~32c | ~$2.55 |
| 5.0 kW unit (living room) | ~1.4 kWh | ~46c | ~$3.65 |
| 7.1 kW unit (large living) | ~2.0 kWh | ~65c | ~$5.20 |
These are average figures assuming the unit is running continuously at moderate output. In practice, once the room reaches temperature, the heat pump throttles down and uses less electricity. Actual daily costs are often 20-30% lower than the table above because the unit isn't at full output the whole time.
4. Monthly and seasonal costs
What does this add up to over a winter? Taking a 5.0 kW unit in a Waikato home as a typical example:
- Winter month (June-August): 6-8 hours/day usage = $70-$100 per month
- Shoulder month (April-May, September-October): 3-4 hours/day = $30-$50 per month
- Summer (cooling): occasional use, 1-2 hours/day on hot days = $10-$20 per month
- Full year estimate: $350-$600 total for a single main living area unit
For a whole-home setup with 2-3 units, multiply accordingly - though bedroom units typically run fewer hours than the main living area unit.
5. Heat pump vs other heating costs
Here's how heat pump running costs compare to other common heating methods in NZ, based on delivering the same amount of heat to a room:
| Heating method | Cost per kWh of heat | Relative cost |
|---|---|---|
| Heat pump (COP 3.5) | ~9c | Baseline |
| Wood burner (good quality) | ~8-12c | Similar (depends on wood price) |
| Natural gas heater | ~16-20c | ~2x more expensive |
| LPG gas heater (bottled) | ~22-28c | ~2.5-3x more expensive |
| Panel heater / fan heater | ~32c | ~3.5x more expensive |
| Oil column heater | ~32c | ~3.5x more expensive |
The numbers are clear: heat pumps are the cheapest way to heat a room electrically, and competitive with wood burners. Panel heaters, oil columns, and fan heaters are dramatically more expensive to run for the same heat output. If you're currently using plug-in electric heaters, a heat pump will typically cut your heating costs by 60-70%.
6. Why your actual costs might differ
The figures above are based on averages. Your real costs will depend on:
- Your electricity rate: rates vary from 25c to 38c/kWh depending on your retailer and plan. Shop around - a few cents per kWh adds up over a winter.
- Your heat pump's actual COP: a premium unit with COP 4.5 will cost 20-25% less to run than a budget unit with COP 3.2 doing the same job.
- Your home's insulation: a draughty home loses heat fast, which means the heat pump works harder and longer to maintain temperature.
- How you use it: running the unit at 24 degrees instead of 21 degrees increases costs significantly. Each degree above 20 adds roughly 8-10% to running costs.
- Outdoor temperature: colder days mean lower COP and higher electricity consumption. The coldest Waikato days cost more per hour than average winter days.
7. Tips to reduce your heat pump running costs
You can't change the laws of thermodynamics, but you can use your heat pump smarter:
- Set it to 20-21 degrees, not 24. Heating to 21 instead of 24 can reduce running costs by 20-30%. Most people find 20-21 comfortable with a jumper on.
- Use the timer.Set it to come on 20 minutes before you wake up and turn off when you leave. Don't heat an empty house.
- Close doors and curtains. Reduce the volume of air the heat pump needs to condition. Heavy curtains over windows make a real difference, especially single-glazed ones.
- Don't use "auto" fan speed in winter. Set the fan to low or medium. Auto mode often ramps to high, which is noisier and pushes warm air up to the ceiling. Low/medium gives more even heat distribution.
- Point the louvres down in winter.Hot air rises, so directing the airflow downward pushes warmth to where you're sitting, not the ceiling.
- Clean the filters regularly. Dirty filters restrict airflow and make the unit work harder. Check them monthly in winter - it takes 2 minutes and saves real money.
- Fix your insulation first. Spending $2,000 on underfloor and draught-stopping will reduce your heat pump running costs every year for the life of the house. The payback is faster than upgrading to a more efficient heat pump.
8. Smart usage patterns
The most cost-effective way to use a heat pump follows your daily routine:
- Morning: timer turns on 20-30 minutes before your alarm. Set to 20 degrees. The unit runs at higher output initially, then throttles back once it reaches temperature.
- During the day (home): leave it running at 20-21 degrees. Once at temperature, it uses very little power to maintain - often just 300-500 watts.
- During the day (away): turn it off or set to 15-16 degrees if you want to take the edge off for when you return.
- Evening: turn on 20-30 minutes before you get home (use the Wi-Fi app). Run at 20-21 degrees through the evening.
- Night (bedroom): 16-18 degrees is better for sleep than 21. Set the timer to turn off or drop to 16 at bedtime. Research shows cooler sleeping temperatures improve sleep quality.
The Wi-Fi app on most modern heat pumps makes scheduling easy. Set it once and forget about it. If your unit doesn't have Wi-Fi, the remote control timer works just as well for basic on/off scheduling.
Frequently asked questions
How much does it cost to run a heat pump per hour in NZ?
A typical 5 kW heat pump costs roughly 40-50 cents per hour to run in heating mode at current NZ electricity rates (around 30-35c/kWh). That is because a heat pump with a COP of 3.5 only draws about 1.4 kW of electricity to produce 5 kW of heat. Actual cost varies with your power plan, the outdoor temperature, and the unit's efficiency.
Are heat pumps cheaper to run than gas heaters in NZ?
Yes - heat pumps are significantly cheaper to run than gas heaters in New Zealand. A heat pump produces 3-5 kW of heat for every 1 kW of electricity consumed, while a gas heater converts gas to heat at roughly 80-90% efficiency. At current NZ energy prices, heat pump running costs are typically 50-70% lower than natural gas and even more compared to bottled LPG.
What is COP and why does it matter?
COP stands for Coefficient of Performance and it tells you how efficient a heat pump is. A COP of 4.0 means for every 1 kW of electricity the unit consumes, it produces 4 kW of heat. Higher COP means lower running costs. COP drops as outdoor temperatures fall, so a unit rated COP 5.0 at 7 degrees might only manage COP 3.0 at minus 2 degrees.
How much electricity does a heat pump use per day?
A typical 5 kW heat pump running 8 hours per day in winter uses roughly 10-12 kWh of electricity per day, costing about $3-$4 at current NZ rates. In milder weather or with good insulation, consumption drops to 5-8 kWh per day. In summer cooling mode, usage is typically lower because the temperature differential is smaller.
Do heat pumps use a lot of electricity on standby?
Modern heat pumps use very little electricity on standby - typically 2-5 watts, which costs less than $5 per year. Leaving the unit in standby is fine and actually preferable to switching it off at the wall, because the crankcase heater keeps the compressor oil warm and prevents damage on cold startup.
Is it cheaper to leave a heat pump running all day?
Generally no - it is cheaper to run your heat pump only when you need it rather than leaving it on 24/7. However, turning it on 15-30 minutes before you need the room warm (rather than blasting it on high when you walk in) is more efficient. Use the timer or Wi-Fi app to schedule it around your routine.
