Paul Novus filters

No. The Focus 200 takes its own filter size, while the Novus 300 and Novus 450 share one set. The Climos (F) 200 uses a different size again. Check the series name and model number on the unit before ordering, then choose the G4+G4 or G4+F7 version (M5+M5 or M5+F7 for Climos).

It depends on the model. The Paul filter sets we stock come in these combinations:

• Novus 300/450 and Focus 200 — G4+G4, or G4+F7 with a fine F7 (ePM1) supply filter
• Climos (F) 200 — M5+M5, or M5+F7

Because Passive House buildings get all their fresh air through the MVHR unit, the version with the F7 supply filter is usually the better choice for indoor air quality.

Two pieces of information on the unit's front panel confirm your exact Paul model:

• The series name, such as Novus or Focus
• The longer alphanumeric model code, which specifies airflow capacity

Both help match you to the correct filter set, especially where multiple airflow variants share a series name.

Paul Wärmerückgewinnung is a German pioneer of ventilation systems designed for Passive House and low-energy buildings, with several unit series built around very high heat-recovery efficiency. Depending on the model, Paul units use G4, M5 and F7 filters.

As a rule, no. For ordinary pollen and house-dust allergies, a properly sized F7 filter changed on time already removes the large majority of what causes symptoms — and F7 is the finest class we stock for Paul: as G4+F7 for the Novus 300/450 and Focus 200, and as M5+F7 for the Climos (F) 200. A denser filter would also have a higher pressure drop, which means more fan electricity and, in units without much filter area, potentially less air. If symptoms persist with fresh F7 filters, check first whether the filters are being changed often enough and whether they sit tightly in their housing, with no air slipping past the edges.

Check them every 3 months and replace them at least every 6 months. In a Passive House the MVHR unit supplies all the fresh air, so a clogged filter shows up quickly as stuffier air and more fan noise. Change the supply filter sooner during pollen season or if you live near a busy road, and keep a spare set at home so you never run the unit on saturated filters.