Zehnder MVHR filters

Zehnder ComfoAir units use two filter classes:

• G4 (ISO Coarse) — protects the heat exchanger; used on the extract side
• F7 (ePM1) — for the supply air, capturing fine dust and pollen

For most ComfoAir models we stock both a G4+F7 set and a G4+G4 set. The G4+F7 set is the better choice for allergy sufferers and homes near busy roads.

Find the exact model on the unit's front panel — for example ComfoAir Q350, Q450 or Q600, ComfoAir 350/500/550, ComfoD 350/450/550 or Zehnder EVO. That is the fastest way to match the correct filter set in our catalogue. If the label is missing, measuring the extract and supply filters directly identifies the right size just as reliably.

Because ComfoAir's F7-class supply filter is specifically designed to capture fine airborne particles including pollen, it can load up faster during spring and early summer than during the rest of the year. Checking filters monthly during peak pollen season, even within the standard 3–6 month replacement window, helps maintain steady airflow and allergy protection.

Yes. The ComfoAir Q350, Q450 and Q600 — and the ComfoAir E350 — all take the same filter set, available as G4+F7, G4+G4 or an activated carbon version. Older ComfoAir models (70, 160, 180, 200, standard 300/375 and 350/500/550) each take a different size, so check your model on the front panel before ordering.

Not necessarily. In most ComfoAir models the warning is a runtime timer set at commissioning, so it tells you that the configured interval has elapsed, not that it has measured a loaded filter. In a dusty location the filters can be visibly grey well before the warning appears; in a lightly used flat they can still look serviceable when it does. Treat the warning as a prompt to look rather than a verdict: open the unit and check both filters, replace them if they are grey or the airflow has dropped, and reset the reminder afterwards in the control panel or the app so the next one is timed correctly.

For most ComfoAir models both, and the choice is yours; for a few, such as the ComfoAir 70, 160 and 200, we stock originals only. Original Zehnder filters are made by the manufacturer; our compatible filters are produced at EU manufacturers' facilities to the same ISO 16890 classes and cut to the exact ComfoAir housing dimensions. In use there is no meaningful difference in filtration as long as two things match — the class (G4 on extract, G4 or F7/ePM1 on supply) and the dimensions of your specific model. The difference is price, and it is usually noticeable. What matters far more than the choice is checking your exact ComfoAir or Q model code before ordering, since filter sizes differ between models — only the ComfoAir Q350, Q450, Q600 and E350 share one set.