Filters for a commercial air handling unit (AHU) are a different proposition to the pleated panels in a domestic MVHR. They are larger, often bag (pocket) filters, usually run at higher airflow, and a blocked set shows up directly on the unit's pressure readings and energy use. This guide covers what you need to know for two of the most common ranges in UK plant rooms — Systemair Topvex and Geniox — and how to order the right filters.
How AHU filters differ from domestic MVHR
- Bigger and often bag-type. Commercial units frequently use deep bag/pocket filters for more dust-holding capacity and lower resistance at high airflow, alongside or instead of flat panels.
- Separate supply and extract. Larger units take individual supply and extract filters rather than a single small kit, and some take multiple filters per airflow.
- Pressure matters. AHUs are often fitted with a differential-pressure gauge or sensor across the filter; a rising reading is your cue to change, not just the calendar.
Systemair Topvex filters
The Topvex range covers compact commercial AHUs. The two common families are the FC (flat compact) units — FC10, FC15, FC20 and FC25 — and the TR units — TR03 up to TR09, including the TR1000/TR1500/TR2000 designations. Each takes a specific supply and extract filter, bought individually. Note that some older Topvex units changed filter size over time — the TR04, for instance, differs before and after 10 May 2010 — so check your unit's age if a listing flags a date. Browse Systemair Topvex filters.
Systemair Geniox filters
Geniox is Systemair's larger modular AHU platform. Filters are supplied as kits by unit size (for example Geniox 10 and Geniox 11) and by grade — typically M5 for general protection and F7 for finer supply-air filtration. Choose the grade your unit was commissioned with, or step the supply up where the application calls for cleaner air. Browse Systemair Geniox filters.
What grade for a commercial unit?
Commercial filters use the same ISO 16890 classes as domestic units (Coarse, ePM10, ePM2.5, ePM1) and the older EN 779 grades (G4, M5, F7, F8, F9). As a general pattern, a coarser grade protects the heat exchanger on the extract side and a finer grade (commonly F7 / ePM1) handles supply air, stepping up to F8/F9 where indoor air quality requirements are higher. Our filter grades guide explains the full picture and the old-to-new conversions.
How often to change — and watch the pressure
Interval depends on the environment, but commercial units in dusty or urban settings are typically serviced more often than domestic MVHR. The reliable signal is the differential pressure across the filter: as the filter loads, resistance rises, the fan works harder and energy use climbs, so most operators change at a set pressure drop or on a planned maintenance schedule, whichever comes first. Letting the pressure drop climb is a direct cost on the electricity bill.
Genuine vs compatible on commercial units
On commercial plant, genuine filters matter more, not less: correct media and a proper seal keep the unit within its commissioned performance, protect the warranty, and avoid unfiltered bypass that fouls the heat exchanger. We supply genuine Systemair Topvex and Geniox filters, sourced from the same supply chain as the manufacturer, at trade prices.
Ordering the right filter
Order by the genuine part number where you have it, or by the exact unit model and the grade it was specified with. If you are working from a filter schedule or a planned-maintenance list, send it over and we will quote the full set.
Related guides
- MVHR Filter Grades Explained: ISO 16890, G4, M5 and F7
- How to Find the Right Replacement MVHR Filter for Your Unit
- Commercial MVHR: A Guide to Heat Recovery Ventilation for Non-Domestic Buildings
Frequently asked questions
What filters does a Systemair Topvex unit take?
Each Topvex FC and TR unit takes a specific supply and extract filter, ordered individually by model. Check your exact model (and its age, for older TR units) or the part number.
What grade are Geniox filters?
Geniox filter kits are commonly available in M5 and F7 grades by unit size. Match the grade your unit was commissioned with, or step the supply grade up for cleaner air.
How do I know when to change a commercial AHU filter?
Watch the differential pressure across the filter as well as the calendar. A rising pressure drop means the filter is loading and the fan is working harder — change at the recommended pressure drop or on your planned maintenance schedule.
Do commercial units use the same ISO 16890 grades as domestic?
Yes — the same Coarse, ePM10, ePM2.5 and ePM1 classes apply, usually a coarser extract filter and a finer (F7 / ePM1 or higher) supply filter.