Contact us
Questions, wishes, ideas?
We are happy to be there for you personally.
The concentration of pollutants inside the vehicle is four times higher than outside.
03/25/2025
... at least in 2001.
The reason for this high value was the particle filters, which were still very simple at the time and worked according to the so-called "coffee filter principle". A satisfactory solution for filtering particulate matter at the time - but no longer in times of increasing health awareness. In addition to particulate matter, there are other pollutants in the air that can enter the vehicle interior unhindered when using a simple particle filter and accumulate over the entire driving period.
To prevent this, it is not only worth upgrading to an activated carbon or even HEPA filter, but also changing it regularly. We explain what to look out for below.
"Better too early than too late"
A motto that also applies when replacing a cabin air filter. As a rule of thumb, however, you can also remember "O to O", i.e. Easter to October or every 15,000 km, similar to changing tires.* The reason for the need for regular replacement is the approximately 500,000 liters of outside air that modern vehicles channel into the interior every hour. Cabin air filters remove dirt particles, pollutants and germs and store them inside. However, as even the best filter only has a limited absorption capacity, it should be changed regularly. Otherwise, it can only fulfill its tasks to a limited extent and even hinder the supply of fresh air - and thus very quickly reach a value like 2001 again Good to know: If you are often on the road in areas with particularly high air pollution - for example in large cities or areas with sandy/dusty ground - shorter replacement intervals may make sense.
1. identify the installation location of the filter
You have read correctly. The location of the filter is not always the same. Some are located in the engine compartment near the windscreen wiper, some under the glove compartment or, as in the Ford Focus and Mondeo, very cleverly behind the accelerator pedal. You can check where exactly the filter is located in your vehicle in the manufacturer's documentation or research it online.
2. note the installation direction
Practical experience shows that around one in three cabin air filters is installed in the wrong direction. However, if installed incorrectly, this can lead to premature saturation or even failure of the filter. There are several reasons for this. Firstly, it is the design of multi-stage filters: a coarse stage made of paper first filters out the largest particles such as dust or pollen from the supply air before further, finer stages take over the filtration of bacteria, spores and other substances. If the filter is installed in the wrong direction, the finer layers have to take on work that they are not designed for, resulting in premature saturation. The second is how the filter is inserted into the holder. Incorrect installation can result in air bypassing the filter and thus entering the vehicle uncleaned.
Good to know: Many filters now feature a small arrow indicating the direction of the air flow. You can use this as a guide. What you should never rely on is how your previous filter was installed. It is best to start the engine and check by hand which direction the air is coming from. This will allow you to identify the direction of the air flow.
3. also clean the evaporator!
When changing the filter, an important step is often not considered: cleaning and disinfecting the air conditioning evaporator. This is located behind the filter and therefore on the cleaned side of the air duct. This is not an issue if the evaporator is cleaned regularly. It only becomes a problem if the condensate creates a film of mould and bacteria and germs are released into the already filtered air. To avoid this, the evaporator and the air duct should definitely be disinfected when the filter is changed.
In summary, it can be said that although changing the filter involves a few pitfalls, it is still a worthwhile effort to get through the allergy season - and every other season - in good shape in the long term.
