Fresh filter, fresh air

New filter

Spring and fall are generally the best times of year to replace the cabin air filter. After all, every driver wants the HVAC system to work efficiently in the summer! However, the air is particularly heavy with pollen and pollutants during the warm, dry months. These are deposited in the filter and rear their ugly head in the winter: foggy or frosty windows, diminishing heating performance, higher pollution level, and unpleasant odors—particularly annoying on cold days when the windows are closed. But aside from the best timing, what are the consequences of waiting too long before changing the filter? Read on for a few reasons to keep it clean ...


Old filter (in the fall)

Did you know? During a one-hour drive, up to 100,000 liters of air flow through the interior of a passenger car, or as much as 540,000 liters in a commercial vehicle. The air drawn from the outside contains pollen, dust, soot, smoke, tire and brake abrasion dust, ozone, gases, and benzene and sulphur compounds. Especially fine particulates can be damaging to health because they penetrate deep into the lungs and can cause inflammation, allergies, and cancer. Cabin air filters keep these harmful substances out of the passenger cabin. Drivers can breathe freely! Clean air and clear windows contribute to health and well-being, while improving a driver’s ability to focus. Since they are installed upstream of the heating or HVAC system, they also protect these components against impurities in the air.


Cleaning is only effective if three conditions are met: the filter element and housing have an exact fit, a high-quality filter medium with uniform, stable pleat geometry is used, and there is a low level of contamination. With MAHLE Original and Knecht filters, the first two criteria are easily met. But the only way to maintain a low level of contamination is by replacing the filter regularly. This is because:

  • The impurities filtered from the air form an ideal breeding ground for mold and bacteria. Odors and health hazards are the result.
  • A clogged filter has only little retention capacity left. The consequences for the occupants: a pollutant concentration that is up to six times as high as at the roadside. And for the heating and cooling system: performance losses and even complete failure.
  • As the contamination increases, so does the flow resistance of the filter. This leads to foggy windows and an increased load on the fan motor.


Focus on service: the MAHLE Aftermarket mirror tag documents the filter change—and reminds you of the next one.

The cabin air filters from MAHLE are technically designed to suit the replacement intervals specified by the vehicle manufacturers, which can sometimes be up to 24 months. However, replacement is generally recommended at least once a year and after 15,000 km. By the way: the best argument for a new filter is the old one. Once you’ve seen it, you won’t forget to have it replaced!


Our clean solutions are available as pure particulate filters (LA), holding back solid substances such as pollen or fine particulates, or as powerful three-layer combination filters with activated carbon layer (LAK), which also absorb odors and gaseous substances such as nitrogen oxides, gasoline fumes, and ozone.


Surface effect: a filter with 200 grams of activated carbon boasts a filter surface of almost 100 soccer fields.

When properly installed, the filter retains the larger particles first and then the smaller ones. That’s why the proper installation direction is crucial to ensure that as much dirt as possible will be absorbed. Detailed installation instructions can be found on the inside of the packaging and at


We regularly provide technical tips relating to the powertrain, thermal management, and mechatronics in automobiles.


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