MVHR maintenance: why and when to clean it

An untended MVHR progressively loses energy efficiency. Regular maintenance is what guarantees the 85–92 % heat recovery quoted by manufacturers is actually delivered.

How does an MVHR work?

MVHR has two independent networks: one extracts stale air from wet rooms, the other supplies filtered fresh air to living rooms. A plate (or rotary) heat exchanger transfers heat from outgoing to incoming air without mixing them, recovering 75–92 % of the energy.

This mechanical elegance has a downside: every link, filter, exchanger, fan, duct, must stay clean. A single dirty part unbalances the whole system.

Why is maintenance so critical?

• The fan over-runs to maintain rated airflow → 20–60 % more power.
• A fouled exchanger no longer transfers heat → 5–15 °C loss in winter.
• Saturated filters re-release captured particles → supply air dirtier than outside.
• Humidity stagnates at vents → mould in dry rooms.

When should you act?

• Increased unit noise.
• Stuffy feeling despite MVHR running.
• Visible condensation at supply vents in winter.
• Persistent kitchen/bath smells.
• Worsened seasonal allergies indoors.
• Unexplained 10–25 % rise in power bill.

The HUMINUS MVHR protocol

1. Calibration measurements: per-vent airflow, exchanger pressure drop, unit power.
2. Endoscopic duct inspection (elbows hold 70 % of deposits).
3. Exchanger removal and washing (warm water + mild degreaser, 24h drying).
4. HEPA H13 vacuuming, fan cleaning.
5. Filter replacement (Eurovent-certified).
6. Room-by-room rebalancing.
7. Summer-bypass and winter-defrost test.

Expected lifespan

HUMINUS expertise on MVHR

HUMINUS services every common brand in Luxembourg: Aldes, Atlantic, Brink, Helios, Paul, Vasco, Zehnder. OEM parts, Eurovent-certified filters, full report within 48h.