Cleaning your heat pump filters is one of the easiest and most effective things you can do to keep your unit running efficiently, reduce power bills, and extend its lifespan. Most manufacturers recommend cleaning filters every few weeks during heavy use — and in New Zealand's variable climate, that means staying on top of it year-round.
Why Clean Heat Pump Filters Matter
The filters in your heat pump's indoor unit trap dust, pet hair, pollen, and other airborne particles. When they become clogged, airflow is restricted and your unit has to work much harder to heat or cool your home. This leads to:
- Higher electricity costs — a dirty filter can noticeably reduce efficiency
- Reduced heating and cooling performance
- Increased wear on the compressor and fan motor
- Poorer indoor air quality, which matters especially in homes with allergy sufferers
According to BRANZ, good ventilation and air quality are key components of a healthy home — and a well-maintained heat pump contributes to both.
How Often Should You Clean the Filters?
As a general guide:
| Usage Level | Recommended Cleaning Frequency |
|---|---|
| Light use (mild seasons) | Every 4–6 weeks |
| Regular use (heating/cooling season) | Every 2–3 weeks |
| Heavy use or pets/dusty environment | Every 1–2 weeks |
Many modern heat pumps have a filter indicator light that tells you when cleaning is due — check your owner's manual.
What You'll Need
- A soft brush or vacuum cleaner with a brush attachment
- Lukewarm water
- Mild dish soap (optional)
- A soft cloth or towel
- A dry, well-ventilated area
No special products are needed. Avoid harsh chemicals or high-pressure water, which can damage the delicate filter mesh.
Step-by-Step: How to Clean Your Heat Pump Filters
Step 1 — Turn Off the Unit
Always switch the heat pump off at the unit (and ideally at the wall) before opening the front panel. Safety first.
Step 2 — Open the Front Panel
Gently lift or swing open the front cover of the indoor unit. Most units have a simple clip or hinge mechanism — refer to your owner's manual if you're unsure.
Step 3 — Remove the Filters
Slide or lift the filters out carefully. They're usually a fine mesh panel, sometimes two separate pieces. Note how they sit so you can replace them correctly.
Step 4 — Remove Loose Dust
Take the filters outside or over a bin and gently tap them to dislodge loose dust. Use a soft brush or vacuum on the lowest setting to remove the bulk of the debris. Always brush in the direction of the mesh, not across it.
Step 5 — Wash if Needed
If the filters are visibly grimy, rinse them under lukewarm running water. For stubborn build-up, use a small amount of mild dish soap and gently work it in with your fingers or a soft cloth. Never scrub hard or use a stiff brush — this can tear the mesh.
Step 6 — Rinse and Dry Thoroughly
Rinse away all soap residue. Shake off excess water and leave the filters to air dry completely in a shaded spot — never put them back wet, as this can cause mould growth inside the unit and damage the electronics.
Step 7 — Reinstall and Test
Once fully dry, slide the filters back into place, close the front panel, and turn the unit back on. Check that airflow feels normal and the unit heats or cools as expected.
Additional Maintenance Tips
- Check the outdoor unit periodically. Clear away leaves, grass clippings, or debris from around the unit to ensure good airflow. Keep at least a clear space around it as per the manufacturer's guidelines.
- Wipe down the indoor unit casing with a damp cloth to prevent dust build-up on vents.
- Book an annual professional service — a qualified heat pump technician will check refrigerant levels, clean the coils, inspect electrical connections, and ensure the unit is operating safely and efficiently. This is something a homeowner cannot and should not do themselves.
- Check out Energywise for tips on getting the most energy efficiency from your heat pump.
Healthy Homes and Heat Pumps
If you're a landlord, note that under New Zealand's Healthy Homes Standards, rental properties must meet specific heating requirements. A heat pump is one of the most common compliant heating solutions. Keeping filters clean ensures your heat pump can actually deliver the required heating capacity. Visit Tenancy Services for full details on landlord obligations.
When to Call a Professional
Filter cleaning is well within a homeowner's abilities, but some heat pump maintenance is restricted or specialist work that must be handled by a qualified technician:
- Refrigerant handling is restricted under NZ law and must only be carried out by a certified refrigeration technician
- Electrical wiring and connections must be done by a registered electrician — see the Electrical Workers Registration Board for more information
- Installation and major repairs should be carried out by a Licensed Building Practitioner or qualified heat pump installer where building work is involved
- If your unit is making unusual noises, leaking water inside, producing strange smells, or not heating/cooling effectively after a filter clean, it's time to call a professional
You can find qualified, local heat pump installers and service technicians on tradedirectory.co.nz.