Why do my filters clog quickly?

Customers often complain about frequent filter changes, especially if they use original filters, which cost 2-5 times more. So more frequent filter changes can cost an extra €30-100 per year. Why does it happen?

1.            Air intake from the wrong side. If the air intake comes from the street, whether from a gravel road or an asphalt road, you will be changing your filters quite often. In dry weather, cars passing by cause dust to enter the ventilation system. An MPL-type filter can become clogged in as little as 2 months.

2.            High air pollution. This can be caused by a temporary source, e.g. ongoing construction, as well as e.g. cultivated fields. There have been cases of filters becoming clogged within a month due to ongoing construction.

3.            The filter used is highly efficient. As a standard, the AHU (air-handling units) arrive with low-efficiency filters: G3, G4, or M5. If you change it to a high-efficiency F7 filter, you’ll notice that it has a shorter lifetime, as it both has a higher resistance and captures more particles. It is also possible to install F9 filters, in which case the filter’s lifetime is reduced even more.

4.            Z-line filters of class M5 or higher are used. In order to save money, users choose price over performance. Some low-cost filter manufacturers, use a small amount of filter material to minimize the cost and release efficient M5 or even F7 filters in Z-line type (with sparse pleats) instead of MPL. Due to their low surface area and high resistance, such filters last up to 2 times shorter.

5.            The manufacturer uses low surface area filters. Recently there is a tendency to increase the size of the filters, as this improves the technical characteristics (lower electricity consumption). Examples are Komfovent, Systemair, Flexit air-handling units. Some manufacturers have filters of similar capacity with thin filters (up to 25 mm) and smaller surface areas. The dust capacity of such filters is considerably lower. So if your neighbor has a Komfovent Domekt R 450 V C6M (filter size 517x278x46 mm) or Systemair VTR 150 (300x130x130 mm), and you have a Zehnder ComfoAir Q 350 (500x160x22 mm), a Salda Smarty 3XV (475x134x25 mm) or an Oxygen X-Air V400 (433x172x31 mm), then your filters will have to be changed 1.5-2 times more often.

How can I reduce the frequency of filter changes?

MPL filters are disposable, and their lifetime is not affected by suction or another cleaning. It is also rarely necessary to reinstall the ducts. In this case, it is possible to use a primary filter box, e.g. a suitable option is the Komfovent FKAP series. A low-cost G3/G4 class filter with a wireframe is used and can be vacuum-cleaned several times. It traps coarse pollutants (lint, insects, coarse dust) and thus prevents the more expensive MPL filter from being clogged quickly. Also, if a primary heater is used in the system, this additional filter prevents these pollutants from entering the heating elements.

Zehnder’s external preheaters (ISO-BOX) are automatically supplied with a pre-filter and insulation (in EPP), so in this case the company itself solves the problem for the users.

If you want to save even more, choose analog filters. A quality CleanFilter analog filter will last just as long as the original and will save you money.