Zehnder Filters & Replacement Filter Sets

Replacement filters for Zehnder MVHR systems

Zehnder filters help protect your mechanical ventilation with heat recovery (MVHR) unit while filtering the air moving through it. This range includes original Zehnder filters for popular ComfoAir, ComfoD and ComfoSpot systems, plus quality-tested, EU-made house-brand alternatives for selected models. Choose from G4+G4 and G4+F7 sets, with an activated-carbon option for selected units, depending on your unit and indoor air requirements.

Each set lists its compatible models, dimensions, filter grades and pack quantity, helping you order by specification rather than appearance. If you need another ventilation brand, browse all replacement MVHR filters.

The quickest route to the right product is simple: find the full model on your unit’s rating label, select that exact model, then confirm the dimensions and grades on the product page.

Find the right Zehnder filter for your model

Zehnder air filters are not universal. Some units share a filter set, but similar model names can use different sizes. Check whether your label says ComfoAir, ComfoAir Q, ComfoD or ComfoSpot and note every number or letter that follows.

Zehnder ComfoAir Q350, Q450 and Q600 filters

The Zehnder ComfoAir Q range includes the Q350, Q450 and Q600 models. Current listings group the Zehnder ComfoAir Q350, ComfoAir Q450 and ComfoAir Q600 filters with the ComfoAir E350. The available sets include original and compatible G4+F7 or G4+G4 options, plus an original activated-carbon option.

Do not confuse a ComfoAir Q350 with an older ComfoAir 350. The current Q350/Q450/Q600/E350 listings specify 500 × 160 × 23 mm filters, whereas the ComfoAir 350/500/550 listings specify 500 × 198 × 14 mm. Always use the dimensions shown on the selected product page as the final check.

Filters for other Zehnder ComfoAir units

Our wider Zehnder ComfoAir filter range covers models including ComfoAir 70, 160, 180, 200, 350, 500 and 550, as well as ComfoAir Standard 300 and 375. Availability of original and house-brand versions varies by model, so use the model selector above to narrow the range before comparing specifications.

Zehnder ComfoD and ComfoSpot filter sets

For central ventilation units in the ComfoD family, view the dedicated Zehnder ComfoD filters, including options for ComfoD 350, 450 and 550. For a ComfoSpot 50 unit, go directly to Zehnder ComfoSpot 50 filters. A shared-looking frame or familiar grade is not enough to prove compatibility; the model and measurements must both match.

How to choose the correct Zehnder replacement filter

Match the unit first and the filtration option second. Before adding a Zehnder filter set to your basket:

1. Read the complete model name. Check the rating plate, front panel or manual for the series, model number and any Q, E or other suffix.
2. Compare the dimensions. If the label is unclear, measure the old filters in millimetres and compare length × width × depth with the listing.
3. Check both filter grades. Confirm whether the set is G4+G4, G4+F7 or another configuration recommended for your unit.
4. Check the pack contents. Most products here are two-filter sets for supply and extract air, but the selected listing is the authority.
5. Choose original or compatible. Both must match the model, size and stated performance; the difference is explained below.

A part number can provide another useful cross-check, but use it only when the product page explicitly lists that code. If you still cannot identify the unit, contact Filter Express for compatibility help with the label details and the old filter’s measurements; if emailing, include a clear photo.

Zehnder G4 and F7 filters explained

G4 and F7 are familiar names from the older EN 779 classification system. ISO 16890 uses particle-size groups such as ISO Coarse and ISO ePM1 instead.

You may therefore see G4 described alongside a rating such as ISO Coarse 60%, or F7 alongside a rating such as ISO ePM1 50%, but these are not universal one-to-one conversions. Check the exact performance stated for each product and read our guide to MVHR filter classes for more detail.

What does a G4 or ISO Coarse filter do?

A G4-class or ISO Coarse filter is designed mainly for larger airborne material. In a typical G4+F7 Zehnder filter set, the coarser filter is used on the extract side to catch household dust, textile fibres, hair, larger pollen and debris before they build up inside the MVHR unit. Its main role is system protection.

What does an F7 or ISO ePM1 filter do?

An F7-class or ISO ePM1-rated filter is a finer filtration option. In a typical G4+F7 set, it is fitted on the outdoor-air supply side, where it captures a greater proportion of fine particulate matter associated with pollen, fine dust, soot, smoke particles and urban pollution. Its role is to improve filtration of the air supplied indoors while also helping to keep the system cleaner.

Finer media can become loaded more quickly in polluted or high-pollen conditions. Do not fit a different grade merely because it sounds stronger: follow the unit documentation and the chosen product’s compatibility information so that filtration and airflow remain appropriate.

When are G4+G4 sets or an activated-carbon option useful?

• G4+G4 sets provide coarse filtration on both air paths and can be suitable where that configuration is specified for the unit.
• G4+F7 sets combine coarse system protection with finer supply-air particle filtration.
• An activated-carbon option is available for selected models to help reduce certain unwanted odours and smoke-related smells as specified on the product page; it does not replace the need for the correct particle filter.

Original Zehnder filters or compatible house-brand alternatives?

Original and compatible Zehnder filter sets can both be appropriate when their specifications match your exact unit. The best choice depends on whether you prioritise manufacturer-branded components or a more affordable replacement option.

• Original Zehnder filters are manufacturer-branded parts supplied for the listed units through Zehnder’s European production network.
• Filter Express house-brand filters are compatible alternatives made in the European Union by selected specialist manufacturers. They are quality checked for fit and filtration performance and are often the lower-cost choice.
• Both options should be assessed by model compatibility, exact size, filter grade and set contents—not by brand name or price alone.

The original range is associated with Zehnder production in the Netherlands, France and Switzerland, while the house-brand range is made in the EU. Because Switzerland is European but not an EU member, European-made is the accurate description for the category as a whole.

When should Zehnder filters be replaced?

As general guidance, inspect the filters regularly and expect replacement around every 3–6 months. The correct interval depends on the unit manual, filter-change indicator, airflow setting and the conditions around your home. A fixed calendar date should never override a visibly dirty or heavily loaded filter or a manufacturer instruction.

Check more frequently when any of the following applies:

• your home is close to a busy road, construction work, industry or another dusty environment;
• pollen levels are high or household members are sensitive to airborne particles;
• there are pets, indoor smoke sources or unusually high occupancy;
• the unit runs at higher airflow for long periods;
• the filters look heavily discoloured or loaded, or airflow has noticeably reduced.

Timely changes help maintain airflow and reduce the amount of dust reaching internal components. Learn more about why regular MVHR filter replacement matters.

How do you change a Zehnder filter set?

Filter replacement is normally a straightforward maintenance task, but the exact sequence varies by unit. Follow the manual, place the system in the recommended safe or standby mode, note the positions of the old supply and extract filters, fit the replacements in the correct orientation, close the unit and reset its filter indicator if required.

Use the “How to change” tab on the relevant product page for model-specific instructions. Disposable MVHR filters should not be washed: water can damage the media and frame. Removing loose surface dust is not a substitute for replacing a loaded filter.

Why order Zehnder filters from Filter Express?

Filter Express brings original and compatible Zehnder filters together in one model-led catalogue. Clear specifications allow you to compare the details that determine fit and performance before you order.

• Model-specific selection for major ComfoAir, ComfoD and ComfoSpot units;
• original and house-brand choices, where available, for different preferences and budgets;
• clear dimensions, grades and set quantities on individual product pages;
• European-made products, including EU-made compatible alternatives;
• replacement guidance and personal compatibility support when the model is unclear.

Start with the model selector above, then compare the available Zehnder filter sets for your unit. Confirm the label, dimensions and grades one final time before ordering. That small check is the most reliable way to protect your MVHR system, maintain suitable airflow and get the filtration option you intended.