How Often Should You Change MVHR Filters?

MVHR filters should generally be checked every 3–6 months and replaced approximately every 6–12 months, depending on the MVHR unit, filter type and environment. Always follow the maintenance schedule provided by your unit manufacturer, as some filters may need replacing more frequently.

Regular filter replacement is one of the simplest parts of MVHR maintenance, but it can have a significant effect on airflow, filtration and the performance of your ventilation system.

If an MVHR filter becomes heavily clogged with dust, pollen and other airborne particles, it becomes more difficult for air to pass through it. Regular checks and replacement help your MVHR system continue supplying filtered fresh air and extracting stale air effectively.

At Ventilation Superstore, you can find replacement MVHR filters for a range of popular ventilation systems and manufacturers.

What Does an MVHR Filter Do?

Mechanical Ventilation with Heat Recovery, or MVHR, continuously extracts stale air from areas such as kitchens, bathrooms and utility rooms while supplying filtered fresh air to bedrooms and living areas.

Filters are used to protect both the incoming air supply and the MVHR system itself.

The incoming-air filter captures particles from the outside air before it enters the property, while filtration on the extract side helps prevent dust and debris from building up inside the heat exchanger and other components.

Depending on the MVHR unit, different filter grades may be available. These can range from basic coarse filters designed primarily to protect the ventilation equipment to finer filters designed to capture smaller airborne particles and pollen.

Ventilation Superstore stocks unit filters from manufacturers including Vent-Axia, Airflow, Domus, Nuaire and Komfovent, with different options depending on the ventilation unit. 

Why Might You Need to Change MVHR Filters More Often?

Where you live and how the property is used can affect how quickly an MVHR filter becomes dirty.

Homes close to busy roads, construction sites or areas with high levels of airborne pollution may require more frequent filter changes. The same can apply during periods of high pollen or where considerable dust is present inside the property.

New builds and recently renovated properties are particularly important. Construction dust can remain in the building after work is completed, which is why checking the filters earlier during the first months of operation is worthwhile.

The type and grade of filter fitted can also influence the maintenance schedule. Always check the documentation for your specific MVHR unit before deciding how frequently your filters should be replaced.

What Happens If You Don't Change Your MVHR Filters?

A dirty filter does not immediately mean that an MVHR system will stop working, but allowing filters to become heavily clogged can restrict airflow through the unit.

Over time, this may mean the fans have to work harder to move air through the system. It can also reduce the effectiveness of filtration and allow more dirt to accumulate within the ventilation unit.

Regular MVHR filter replacement therefore helps maintain airflow, supports effective filtration and protects internal components from unnecessary contamination.

Regular filter replacement is a simple way to support the long-term performance and maintenance of your ventilation system.

How Do You Know When an MVHR Filter Needs Changing?

The maintenance interval provides a useful reminder, but the condition of the filter itself should also be considered.

Signs that it may be time to check or change your MVHR filters include:

• The filter is visibly covered in dust or debris
• An MVHR filter warning or maintenance notification appears on the controller
• Airflow from the ventilation valves appears noticeably reduced
• The system appears to be operating harder or louder than usual
• It has reached the replacement interval specified by the manufacturer
• The property has recently undergone building or renovation work

A filter does not necessarily need to look completely blocked before it is due for replacement.

Can You Clean MVHR Filters Instead of Replacing Them?

This depends entirely on the filter and manufacturer.

Some coarse filters may be suitable for carefully vacuuming or cleaning as part of routine maintenance, while other filter types are designed to be replaced rather than washed.

Do not assume that an MVHR filter is washable. Washing a disposable filter can damage the filter media and affect its ability to capture airborne particles.

Check the maintenance manual for your MVHR unit before cleaning the filter. Where the manufacturer specifies replacement, install a suitable replacement filter instead.

Choosing the Correct Replacement MVHR Filter

MVHR filters are not universal.

Different units can use different filter dimensions, grades and configurations, even when they are produced by the same manufacturer. You should therefore identify the exact make and model of your MVHR unit before ordering replacements.

If you are unsure which filter you require, check the model information printed on the MVHR unit before ordering.

MVHR Filter Replacement Should Be Part of Regular Maintenance

Changing the filters is one of the most frequent maintenance jobs associated with an MVHR system, but it should not be the only one.

The condition of the ventilation valves, external terminals, heat exchanger, condensate drainage where applicable and the wider system should also be checked at the intervals recommended by the manufacturer.

Filters are particularly important because they are constantly exposed to the air passing through the system.

A simple reminder every few months to check them can help prevent a small maintenance task from becoming a larger ventilation problem later.