A heat pump needs two kinds of care. The quick filter clean you do yourself, and a proper service by a technician about once a year.
Skip the first and the unit works harder for less heat. Skip the second and small problems grow into repairs, and there’s a good chance your warranty won’t cover them.
How often should you clean your heat pump filters?
The filters sit behind the front panel of the indoor unit and catch dust before it reaches the coil. A blocked filter chokes the airflow, so the unit uses more power to give you less heat. Keeping them clean can cut energy use by somewhere between 5% and 15%.
How often depends on how hard the unit works:
- In winter, when it runs every day, clean them every couple of weeks.
- At the very least, clean them at every change of season.
- More often if you have pets, live on a dusty gravel road, or have building work going on nearby.
A good habit is to do it on the same day you put the bins out, every second week through the cold months.
How to clean your heat pump filters
- Turn the unit off at the isolation switch. It’s usually on or near the outdoor unit. If you can’t find it, ask whoever services the unit.
- Lift the front panel until it clicks and holds, then slide the filters out.
- Vacuum off the dust with a small brush attachment, or rinse the filters in water no hotter than 50°C.
- Dry them with a soft cloth or in the shade. Make sure they’re completely dry before they go back in.
- Slide them back, close the panel and turn the power back on.
Wipe the front panel with a soft dry cloth while it’s open. Never spray or pour water into the unit itself, and don’t stand on a wobbly chair to reach a high unit.
→ Related: Heat pump winter settings for a lower power bill
How do you look after the outdoor unit?
The outdoor unit does half the work and lives out in the weather. Every six months:
- Clear away leaves, grass clippings and anything growing into it.
- Wash the casing and coil with car-wash liquid, not dishwashing liquid or other detergents, then hose it down gently.
- Check nothing is stacked against it. Keep 30 to 50 cm of clear space around it so it can breathe, and move outdoor furniture, pot plants and bins away.
While you’re there, check the base. The unit should sit on a secure pad or brackets, not straight on the ground, so it doesn’t rust from sitting in the wet and so the water it makes in heating mode can drain away. Have a look after a storm too. A Wellington southerly can pin a surprising amount of debris against the back of the coil.
What if you live by the coast or in a geothermal area?
Salt air and geothermal sulphur both speed up corrosion. Living by the sea doesn’t mean your unit will fail, but it does mean more care. Your installer can tell you which corrosion zone you’re in, from C1 (low) to C5 (very high). In the higher zones, rinse the outdoor unit more often, keep up any protective coating that was applied, and book services more often than once a year.
When should you book a professional heat pump service?
Book a service by a qualified technician once a year. Do it in autumn, before you need the heat pump every day and before every installer in town is busy with the first cold snap.
Homes near the coast, in geothermal areas like Rotorua, or with a unit that runs most of the year may need a service more often. Your service provider can suggest a schedule for your spot.
What does a heat pump service cover?
A professional service goes further than the filters. Depending on the business, it can include:
- a deeper clean of the indoor coil and fan than you can do at home
- clearing salt and dust from the drain tray and checking the drain runs freely
- cleaning salt, dust and grime from the outdoor coil
- checking the outdoor unit is level, secure and clear
- checking it heats properly and the controls and timer work
- looking for corrosion, damage or anything loose
When you book, have the model numbers of the indoor and outdoor units ready. They’re on the labels on the side of each unit. Tell the technician about anything you’ve noticed, like a new noise or a room that takes longer to warm. It helps them bring the right parts the first time.
Ask what’s included before you book, because services vary. A routine “regas” shouldn’t be on the list, and our guide to heat pump problems explains why, along with what to check if the unit isn’t working right between services.
What does your warranty expect you to do?
This is the part most owners miss. The main brands’ warranty cards make the owner responsible for some basic care:
- cleaning the air filters regularly, and replacing them when needed
- keeping the air inlet and outlet on the outdoor unit clear of dirt, leaves and plants
- keeping the condensate drain clean
- replacing flat remote batteries
- adding corrosion protection if the unit is in a corrosive spot, such as near the sea
Problems caused by skipping these jobs aren’t covered. General’s warranty card goes furthest: its warranty is conditional on that maintenance, and it excludes faults caused by blocked filters. Mitsubishi Electric may ask for maintenance records when it assesses a corrosion claim.
So keep a simple record. Note the date each time you clean the filters, and keep every service invoice with your warranty card, your proof of purchase and the Certificate of Compliance from the install. If you ever make a claim or sell the house, it’s all in one place.
→ Related: Who can install or service a heat pump in NZ
How do you find someone to service your heat pump?
Plenty of businesses service heat pumps of every brand, not just the ones they sell. Find heat pump servicing businesses near you, or start from your town.