Solar panels make electricity. A heat pump uses electricity to move heat into your home. Put the two together and some of the power your heat pump runs on comes off your own roof instead of the grid.
How much comes down to timing, because the sun and your heating don’t keep the same hours.
Can solar panels run a heat pump?
Yes. A grid-connected solar system feeds your home’s switchboard, and whatever is running at the time gets that power first, heat pump included. When the panels make more than the house is using, the extra goes to the grid. When they make less, the grid tops it up. You don’t need a special heat pump for any of this.
A heat pump suits solar because it stretches each unit of power. It moves heat rather than making it, so a typical home heat pump gives out about two to four and a half times as much heat as the electricity it uses. One unit of solar sent to the heat pump becomes several units of warmth in the room.
What solar can’t do is run a heat pump at night. Without a battery, your heat pump only runs on solar while the sun is up.
→ Related: How efficient are heat pumps in NZ?
Does solar line up with when you heat the house?
Here’s the catch. Panels make the most power in the middle of the day, on clear days, in summer. Cloud cuts the output a lot, even light cloud. Panels also do best in sunny regions such as Nelson and Marlborough or the Far North.
Household power use doesn’t follow the sun. It peaks in the morning and the evening, when people are home, cooking and heating. In winter those are exactly the times you want the heat pump on, a frosty Canterbury morning or after dark in Invercargill, and exactly the times the panels make little or nothing.
So the best matches are:
- Summer cooling. A hot afternoon in Hawke’s Bay is when panels are at their best, so cooling lines up well with solar.
- Winter days at home. If someone is home during the day, a heat pump running at midday uses solar directly.
- Winter mornings and evenings. Mostly grid power, unless you have a battery.
→ Related: Heat pump winter settings: temperatures and timers
How to use more of your solar on the heat pump
The trick is to shift some heating into the middle of the day, while the panels are working.
- Warm the house in the early afternoon. Set the timer to bring the living area up to temperature while the sun is still on the panels. A well-insulated house holds that warmth into the evening, so the heat pump has less to do after dark.
- Use a weekly timer or the app. A schedule means the heat pump comes on at the right time even when nobody is home. A smart wi-fi heat pump lets you set that schedule from your phone.
- Watch your solar monitoring. If your system has an app or display showing when you’re making more than you use, check it. That’s the moment to run the heat pump, the hot water and the washing machine.
Do you need a battery to heat your home with solar?
Not to run a heat pump on solar, but a battery is what lets daytime sun heat your home at night. It stores the surplus from the middle of the day for the morning and evening peaks.
Solar is better value with batteries. Without one, it’s better value if your household uses a lot of power during the day.
A battery also lets you sell stored power back at the times it’s worth most. Under rules confirmed by the Electricity Authority in July 2025, households that supply power to the network at peak times, from rooftop solar and batteries, are to be rewarded for it. Ask a solar company to size any battery around your evening heating, not just your lights and fridge.
→ Related: Heat pump running costs: real numbers for NZ homes
Can solar heat your hot water?
Hot water is the easiest place to use solar, because a cylinder stores heat for later. A hot water heat pump can heat the whole tank in the middle of the day on your own power, and you use that hot water in the evening.
Some are sold as solar PV compatible and Smart Grid (SG) ready, so they can take a signal from your solar system and run when there’s surplus. Others have daily and weekly timers you can set to sunny hours. If you go down that road, hot water heat pumps explains how they work and where they go.
Is it better to use your solar or export it?
Every unit of solar power goes one of two ways. You use it in the house, which is self-use, or it goes out to the grid, which is export. Exported power earns a credit from your power company. Self-use means you never buy that unit from the grid at all.
To sell power back you need an import/export meter. Your power company or metering provider can arrange one. Large power companies, those with 5% or more of the market, also have to offer a plan with cheaper off-peak rates. That matters for a heat pump, because heating in cheap off-peak hours and on daytime solar both cut what you pay at peak.
The plain rule: the more of your solar you use at home, the more it’s doing for you. Ask your power company what it pays for export and how its plan charges for evening power, then set your heat pump timers around that.
Who should you talk to before the panels go on?
- Your power company. Ask for your consumption data so you can see when your house uses power, and ask what it pays for export.
- A solar company. They assess your roof for solar. Panels should face north, ideally north-east to north-west, on a 15 to 45° pitch. Shade matters more than most people expect: shade on even one cell can cut a panel’s output by far more than its share. Free tools such as the EECA Solar Power Calculator, the SEANZ Solar Optimiser and NIWA’s SolarView give an early idea of what your roof could produce.
- Your metering provider and lines company, about the import/export meter and connecting the system to the network.
- A heat pump installer, for timers, wi-fi control or a hot water heat pump that can link to solar. Electrical work must be done by a registered electrician, and who can install a heat pump explains the rules.
Where to find a heat pump installer near you
Browse installers who fit wi-fi heat pump control or heat pump hot water, or pick your town to see who works near you.