Cleaning your heat pump filter is one of the few maintenance tasks you can do yourself. It takes about ten minutes, costs nothing, and makes a measurable difference to how well the system runs.
This guide covers the full process: how to remove, clean, dry, and refit your filters correctly, how often to do it, what to check while you have the unit open, and what to do if something does not look right.
It also covers what a filter clean does not reach, because that part of the picture matters too.
Note: this guide covers wall-mounted units. If you have a ducted system, the filter is located in the return air grille on the ceiling. See our ducted heat pump servicing guide. For multi-split systems, the process below applies to each indoor unit individually. See our multi-split heat pump servicing guide.
Start by switching the unit off. Do not attempt to remove filters while the unit is running.
Step 1: Lift the front panel. On most wall-mounted heat pumps, the front panel hinges upward. Press in gently at each side and lift. The filters sit just inside, held in place by clips or slots. Slide them out carefully. Shake or tap the filters lightly outdoors to dislodge loose dust before bringing them inside for washing.
Step 2: Vacuum the filter surface first using a brush attachment. This removes the bulk of accumulated dust without pushing it into the mesh. For a deeper clean, rinse the filters under warm running water. Mild dish soap can be used for heavier build-up. Wash gently and rinse thoroughly until the water runs clear.
Step 3: Set the filters aside to air dry completely. Lean them against a wall or lay them flat in a dry space. Before refitting, inspect the filter frame. Look for rips or tears in the mesh, warping, or damage to the clips. A filter that does not seat properly allows air to bypass it entirely. If the frame is damaged, the filter needs replacing rather than cleaning.
Step 4: When the filter is dry, slide it back into its slot and confirm it sits flush. Close the front panel and restore power.
Every four to six weeks during periods of active use. That is the frequency that keeps the filter functioning as designed.
Most manufacturers list three months as a minimum. In practice, a heat pump running daily through a NZ winter accumulates dust, pet hair, and airborne particles faster than that interval accounts for. Four to six weeks is more realistic for most homes.
The filter condition at each clean is a useful signal. If it is heavily loaded after only a few weeks, the environment is demanding and more frequent cleaning makes sense. If it is barely dusty after six weeks of light use, you can extend the interval slightly.
A blocked filter restricts the airflow the system depends on. The heat pump cannot draw enough air across the internal coil to heat or cool the room properly. Performance drops and run times increase; the system works harder and longer to achieve less.
A blocked filter restricts the airflow the system depends on. The heat pump cannot draw enough air across the internal coil to heat or cool the room properly. Performance drops and run times increase. The system works harder and longer to achieve less.
As the filter loads up further, air begins finding paths around it rather than through it. Bypassed air carries the particles the filter would have caught straight onto the internal coil. Dust and organic material accumulate on the coil surface, where the filter cannot reach them. That build-up reduces heat transfer efficiency and drives the Set and Forget Cost: a gradual, invisible increase in energy use that does not announce itself until it shows up on a power bill.
There is also a mechanical consequence. With airflow restricted at the indoor unit, the refrigerant gas returning to the outdoor unit arrives at the wrong temperature, too hot or too cold depending on the mode. The compressor compensates, running under greater load than it should. Over time, that additional stress shortens the lifespan of the most expensive component in the system. When a compressor fails, the unit is typically written off.
In cooling mode, the bypass build-up on the coil eventually reaches the drain pan below it. Organic matter accumulates in the pan and can block the drain line, which is when water starts appearing inside or below the indoor unit.
A blocked filter is not a minor issue. It is the starting point for a chain of problems that runs through the entire system. For a detailed breakdown of what this looks like over time, see what happens inside a heat pump when it is not serviced.
A heat pump in good condition moves a large volume of air through the system efficiently. A blocked filter reduces that airflow, which means the unit has to run longer and at greater load to reach the temperature you have set.
The degradation is gradual and easy to miss. The power bill goes up a few dollars, then a few more. The room takes slightly longer to warm up. The unit runs through the night. None of it triggers an alert, and each step is small enough to accept as normal.
Cleaning your filter regularly is the simplest thing you can do to keep the system running at the efficiency it was designed for. For more on how internal build-up compounds this effect beyond what a filter clean can address, see how a dirty heat pump affects your power bill.
Some modern heat pumps include a secondary filter behind the main mesh. These are typically smaller, sometimes foam-like in texture, and are designed to capture finer particles, reduce odours, or provide additional air quality filtration. They appear on mid-range to premium models across the main NZ brands.
What they are called and how to care for them varies by brand and model.
Fujitsu/General Airstage Lifestyle range: these units include an Apple Catechin filter and a long-life ion deodorisation filter. The Lifestyle range carries these features; the Comfort range does not. The catechin filter is washable. Rinse gently with warm water and air dry fully before refitting. If you have a Comfort range Fujitsu, you have one main mesh filter only.
Mitsubishi Electric AP Series (AP Classic and AP Smart, among the most commonly installed wall-mounted units in NZ): the AP Series includes a washable Air Purifying Filter that sits behind the main mesh and traps fine dust, pollen, and airborne particles. It is washable, but replacement every 12 months is recommended for best performance alongside regular cleaning. The model number on the label at the base of your indoor unit will confirm whether your unit is AP Series.
Mitsubishi Electric GA and GE Series (older models still common in NZ homes): these units include a catechin filter and an anti-allergy enzyme filter. The catechin filter is washable. The enzyme filter is a replacement item rather than a washable one. Check the label on the filter itself to confirm which type you have.
Panasonic: Panasonic's air quality technology in current NZ models (nanoe-X and nanoe-G) is built into the unit electronics rather than delivered through a physical secondary filter. No maintenance or replacement is required for this system. Panasonic units use a standard washable mesh filter for particle capture.
The key rule across all brands: if the filter is labelled washable, clean it the same way as your main mesh; warm water, air dry completely before refit. If it is not labelled washable, it is a replacement item. Do not rinse a non-washable secondary filter.
If you open your heat pump and find a secondary filter you were not expecting, a professional service technician can identify the type and advise on the correct care interval for your specific unit.
Tenants are legally responsible for cleaning accessible heat pump filters as part of their obligation to keep the property reasonably clean and tidy. The obligation comes with a condition: the unit must be accessible and easy to clean.
Where a heat pump is mounted at a height that requires a ladder to reach, the filter cleaning responsibility sits with the landlord, not the tenant. Many units installed during the Healthy Homes compliance period fall into this category. For a full breakdown of landlord and tenant obligations, see our guide to Healthy Homes heating requirements in 2026.
Landlords are responsible for professional servicing of the internal components regardless of how consistently a tenant maintains the filters. Tenant filter cleaning addresses the surface layer only.
A useful note for property managers: many tenants have not lived with a heat pump before and have not been shown how to clean the filters. Providing a brief written guide at the start of a tenancy sets clear expectations and is more likely to result in regular cleaning than a general instruction buried in a tenancy agreement. For more on managing heat pump maintenance across a rental portfolio, see mould in a rental property heat pump: what landlords need to know.
A filter clean addresses the mesh layer visible when you open the front panel. A professional service addresses what is behind it.
The internal coil, the internal fan, and the drain pan are not accessible through a filter clean. These are the components where meaningful build-up occurs over time, regardless of how consistently the filters are cleaned. Organic material and fine particles bypass the filter gradually and accumulate on the coil surface. The filter slows this process. It does not prevent it.
For a full breakdown of the difference between what a filter clean covers and what a professional service addresses, see heat pump filter clean vs full service: what is the difference.
No. Heat pump filter frames are plastic, and dishwasher heat cycles cause them to warp. A warped frame will not seat correctly in the unit, which allows air to bypass the filter. Rangehood metal mesh filters are dishwasher-safe. Heat pump filters are not. Warm water and mild soap under a tap is the correct method.
Replace the filter. A damaged frame allows air to move around rather than through the filter, which means particles reach the internal coil unimpeded. Replacement filters are available through the manufacturer or most major hardware retailers. Have the unit's model number ready when you order. It is on a label at the base of the indoor unit.
Replace the filter if the mesh is torn, the frame is warped or cracked, the filter no longer sits flush in the unit, or if cleaning does not restore a reasonable level of clarity to the mesh. A filter that is intact and seats properly can generally be cleaned and reused indefinitely. Some manufacturers suggest replacement after a few years as a precaution, but condition is a more reliable guide than age.
The filter is not the source of heat pump odours. The smell comes from mould or organic build-up on the internal coil or in the drain pan. These are components a filter clean does not reach. If a smell persists after cleaning the filter, the unit needs a professional service. For more on what causes heat pump smells and what resolves them, see why does my heat pump smell: causes and what to do.
No. Running the unit without the filter allows unfiltered air to pass directly across the internal coil. Every particle that would normally be caught goes straight into the unit instead. Even a short period without the filter adds to the internal build-up the filter is designed to prevent. Wait until it is fully dry before refitting.
A main mesh filter that is cleaned regularly and refitted carefully can last for many years. There is no fixed replacement schedule that applies universally. Replace when the mesh is damaged, when the frame no longer seats properly, or when the filter cannot be cleaned to a reasonable standard. Some manufacturers include a suggested replacement interval in their documentation; worth checking if you have access to the manual for your unit.
Not sure what condition your heat pump is actually in? The Home Energy Health Assessment takes about three minutes and gives you a clear picture of where your system stands.