Old and new MVHR filters – what’s the difference?
Most people only replace their MVHR filters once they look obviously dirty. But even a filter that seems fine at first glance may no longer be cleaning the air properly. Some try shaking it, vacuuming it or blowing it out – but that only helps for a short while. Why is that, and what’s the real difference between old and new filters?
ℹ️How does an MVHR filter work?
The filter is designed to capture dust, pollen and other pollutants.
- The higher the filter class (e.g. F7 or F9), the more – and the finer – particles it can trap.
- Particles build up not only on the surface but also deep inside the filter – which is why vacuuming never removes them completely.
Over time, the filter becomes clogged, air struggles to pass through, and problems start to appear.
ℹ️What happens when a filter gets old?
⚡ Higher energy use and more noise
- If the MVHR unit does not have a constant airflow function, the air starts flowing more weakly – ventilation in the home becomes less effective.
- If the MVHR unit does have a constant airflow function, the fan runs at higher speeds – which means increased electricity consumption and more noise.
Example (based on the Systemair Save VSR 300 calculator):
| Operating mode | Filter | External pressure, Pa | Airflow, m³/h | Fan power, W | Noise, dB(A) |
|---|---|---|---|---|---|
| Initial mode | Clean, +0 Pa | 150 | 200 | 36.4 | 63 |
| Without constant airflow | Used, +50 Pa | 200 | 168 | 36.4 | 64 |
| Max. without constant airflow | Clogged, +280 Pa | 430 | 47 | 36.4 | 67 |
| With constant airflow | Used, +50 Pa | 200 | 200 | 43.3 | 65 |
| Max. with constant airflow | Clogged, +280 Pa | 430 | 200 | 81.1 | 71 |
In short: an old filter = poorer air + higher bills.
🚨Hygiene issues and odours
Pollen, insects and fluff build up inside the filters. Over time, they start to break down, allowing bacteria or mould to form. This can worsen air quality and cause unpleasant odours.
🔧 Risk to the Ventilation unit
When a filter becomes heavily clogged, air can leak through small gaps and bypass the filter. Dust then gets into the heat exchanger, heater or fans – which can lead to breakdowns.
❓When should you change the filters?
Manufacturers usually recommend changing filters twice a year – in spring and autumn.
However, the interval should be adjusted to your surroundings:
- in the countryside or a cleaner environment – less often,
- near a busy road or construction site – more often.
⚠️ You can only vacuum filters with a wire frame or filter material a few times, but they will never be as effective as a new one.
ELECTROLUX STAR EPVS-200 G4+G4 Filter set (Standard)
Ex VAT: £4.87
| Manufacturer of MVHR | ELECTROLUX |
| Manufacturer | CleanFilter |
| Air handling unit | ELECTROLUX STAR EPVS-200 |
| Filter dimensions | 210x175 |
| Class EN779 | G4+G4 |
| Class ISO16890 | Coarse 65% |
| Protection level | Basic: larger solid particles, dust, fluff. |
| Quantity of filters | 2 |
| Advantages |
|
Wolf CWL-2-325/400 4xG4 Filter set (filtering material for frames)
Ex VAT: £4.25
| Manufacturer of MVHR | WOLF |
| Manufacturer | CleanFilter |
| Air handling unit |
|
| Filter dimensions | 500x200 |
| Class EN779 | G4x4 |
| Class ISO16890 | Coarse 65% |
| Protection level | Basic: larger solid particles, dust, fluff. |
| Quantity of filters | 4 |
| Advantages |
|
| Manufacturer product number | 1669551 |
| Remarks | The filter set is designed to protect the MVHR from bigger particles. If you want to clean the supply air from small particles such as pollen and smog, choose the F7 class supply air filter. It is available in our shop. |
Mitsubishi Lossnay LGH-35RX 4xG4 Filter set (Standard)
Ex VAT: £4.10
| Manufacturer of MVHR | Mitsubishi |
| Manufacturer | CleanFilter |
| Air handling unit | Lossnay LGH-35RX |
| Filter dimensions | 399x183 |
| Class EN779 | G4x4 |
| Class ISO16890 | Coarse 65% |
| Protection level | Basic: larger solid particles, dust, fluff. |
| Quantity of filters | 4 |
| Advantages |
|
| Manufacturer product number | PZ-35RF8-E |
| Remarks | Not suitable for RVX3 models. Please verify filter dimensions before ordering. |
Brink Renovent Excellent 300/400/450 G4+G4 Filter set (Standard)
Ex VAT: £5.36
| Manufacturer of MVHR | Brink |
| Manufacturer | CleanFilter |
| Air handling unit |
|
| Filter dimensions | 185x525x5 |
| Class EN779 | G4+G4 |
| Class ISO16890 | Coarse 65% |
| Protection level | Basic: larger solid particles, dust, fluff. |
| Quantity of filters | 2 |
| Advantages |
|
| Manufacturer product number |
|
| Remarks | The filter set is designed to protect the MVHR from bigger particles. If you want to clean the supply air from small particles such as pollen and smog, choose the F7 class supply air filter. It is available in our shop. |
Why choose CleanFilter?
- Same quality as original filters, but at a price 2–3 times lower.
- This means you can replace filters more often and ensure clean air at home.
- All filters comply with hygiene standards (VDI 6022).
👉 In short: a new filter ensures fresh air, lower bills and a longer lifespan for your MVHR unit.