How often should you change your MVHR filters?
Updated October 28, 2026 · 4 min read
Change your MVHR filters about every six months and inspect them in between. Traffic, building work, pollen and pets may make them dirty sooner, while the screen reminder is only a timer.
Replace the filters about every six months
Most manufacturers advise changing heat recovery ventilation (MVHR) filters about every six months, with inspections in between. Treat that as a practical starting point rather than a date carved into the casing. How quickly the filters become dirty depends on the air passing through them.
Your ventilation unit has at least two filters. One sits on the fresh air supply entering the home, often marked “supply” or “toevoer”. The other is on the extract air leaving the rooms, usually marked “extract” or “afvoer”. Both need checking, even if the display only gives you one filter message.
Regular replacement matters because the unit must keep air moving through the filter material. As dirt builds up, the fans have to work harder. Leaving the filters in place indefinitely does not make them better value. It simply gives the ventilation unit a more difficult job.
Some homes need earlier filter changes
You may need to replace the filters more often if you live near a busy road. The incoming-air filter has more outdoor particles to catch, so the usual six-month interval may be too long. Check it between planned changes rather than relying on the calendar alone.
Building work can also load filters more quickly, whether the work is taking place in or around the home. In the countryside, pollen periods can have a similar effect on the supply filter. Animals are another reason to inspect the filters more frequently.
There is no single shorter interval that suits all these situations. The useful approach is to keep the manufacturer’s approximate six-month recommendation as your baseline, then bring the replacement forward when the operating signs show that the filters are already restricting the system.
Signs that the filters are becoming blocked
Reduced airflow in the rooms is one of the main signs of dirty filters. The ventilation unit may still be running, but less air reaches the supply valves or leaves through the extract valves because the filters are resisting the flow.
You may also hear more noise from the unit. This happens because the fans are working harder to pull or push air through the loaded filter material. Higher electrical consumption can follow for the same reason. Noise by itself does not tell you which filter is responsible, so inspect the filters rather than guessing from the sound.
Dirty filters can eventually allow the heat exchanger to become dirty as well. That is why the regular inspection matters even when the airflow still seems acceptable. You do not need to wait for lower airflow, extra noise and increased consumption to appear together before changing a filter.
The filter message is usually a time reminder
On many ventilation units, the “filter” message is triggered by a timer. It does not measure how much dirt is actually in the filters. The reminder can therefore appear before they are heavily loaded, or after they should already have been replaced.
When the message appears, inspect the filters and consider the conditions around your home. A busy road, recent building work, pollen or animals may explain why they need changing. If the filters were changed recently, check whether the filter counter was reset at that time.
After fitting new filters, reset the counter so that the next reminder starts from the replacement date. Depending on the model, this is done on the ventilation unit’s screen, a separate controller or an application. The exact menu and button sequence vary, so use the manufacturer’s manual for your unit rather than trying every button and hoping for diplomacy.
Cleaning does not replace a scheduled change
A fine F7 filter must not be washed or vacuumed. Either method can damage the filter material, even if it looks tidier afterwards. When an F7 is dirty, replace it.
A vacuum cleaner can be used on a coarse G4 filter between replacements. This may help temporarily, but it does not take the place of fitting a new filter at the normal change interval. Washing or vacuuming should not be treated as a way to keep the same filters running without limit.
When fitting a new filter, follow the airflow arrow printed on its frame. A filter installed backwards can filter poorly and may deform. If you are unsure how to open the ventilation unit or reach the filter compartments, follow the manufacturer’s manual for that model.
Keep the interval tied to your actual system
A sensible routine is to note when the filters were replaced, inspect them before the next planned change and pay attention to airflow and fan noise. The screen reminder is useful, but it should sit alongside those checks rather than replacing them. Resetting a timer does not clean a filter, and cleaning a G4 does not restart its service life.
When replacement time comes, VMCDirect lists its own-brand filters by ventilation unit model, by the reference printed on the old frame or by dimensions in millimetres, written as width × height × thickness. Use the exact model name from the unit’s identification plate if you have it.
Frequently asked questions
Should I change MVHR filters every six months exactly?
About every six months is the recommendation from most manufacturers, but inspect the filters in between. Busy roads, building work, pollen periods and animals can mean changing them sooner.
Can I wait until the ventilation unit shows a filter message?
Not always. Many filter messages are based on elapsed time rather than actual dirt, so the warning may appear too early or too late.
Why does the filter message remain after replacement?
The filter counter probably needs resetting. This may be done on the unit, controller or application, depending on the model, so check the manufacturer’s manual for the exact procedure.
Can I vacuum the filters instead of replacing them?
You may vacuum a G4 filter between changes, but it still needs replacing. Do not vacuum or wash an F7 filter because this can damage its filter material.