The cabin air filter is the filter that cleans the air that comes into the interior through the ventilation of the air conditioning system. It prevents dust, pollen and other airborne material from entering the cabin compartment of your car. This comes in handy particularly if you have allergies or other respiratory problems.
Some manufactures recommend that you get it replaced every 15,000 kilometres, while others say it will last more than 20,000 kilometres. But it all depends on how much you drive and where. For instance, if you drive in heavy traffic inside Dhaka, the air quality is poor. In this case you might need to replace the filter more often than recommended. However, that also could be true during the dry weather when there is a lot of dust.
Some signs that you need a new cabin air filter are persistent bad odours. Another sign is reduced air flow through your air conditioning system, such as when you crank up the fan to maximum and you get more noise than results. Even if you don't have these warnings, we recommend that you have the filter checked at least once a year. Checking the filter is a fairly easy process and you may be able to do that yourself.
All cars have their cabin air filters placed behind the glove box and can be easily accessed ones the glove box freed from its fasteners. Most of these replacement filters are inexpensive, as in Tk400 or more at an automotive parts store, and they will also install it for free of cost.
When your mechanic recommends you get a new cabin air filter, ask to see the current one. Depending on how long the filter has been in service, you might be shocked to see what has been trapped in it: leaves, insects, soot and grime. Basically anything that comes in contact with incoming air. Now, you will have a clear idea about when it's time for a new cabin air filter.