By keeping your air conditioning filter clean you allow the unit to properly move the air from the room, through the evaporator and out the vent, making the room cool and comfortable. A clogged or blocked filter prevents the intake of air and will make your air conditioner work harder, leading to higher electric bills and poor performance by the unit.
The air conditioning filter is important in preventing build up of dust, grease and other small particles within the air conditioning unit itself. Without the filter all the dust and debris that are trapped by the filter would be deposited directly on the fins, resulting in that space becoming clogged and blocked. Once the air flow is restricted around the cooling area, the system is just not able to produce cold air. In addition without the filter the debris and dust would stick to the fins as they are moist due to the moisture produced in the cooling process, especially in humid climates. This can and will lead to bacteria growth in the system that in turn blows this bacteria back into the air that you are breathing in.
Cleaning the window filter on a regular basis not only helps with cooling but also with the efficiency of the system. A good idea is to clean the filter once before turning on the air conditioner in the spring and then again every three to four weeks while the system is being used. If you live in an area where there is lots of fine dust, smokers in the house or pets you may find that cleaning the filter every two weeks is more beneficial.
Window air conditioning filters are the easiest to clean and are typically made of either a sturdy foam type material or a fine mesh. The most common and recommended type of filter is made of polypropylene, which is actually electrostatic and will trap small particles. To clean these types of mesh screens simply wash in warm soapy water and rinse well. Always allow the filter to completely dry before putting it back in the unit. Foam filters should be replaced with a new filter that can be made at home from foam sheets bought at a home supply store.
A large outdoor conventional air conditioning filter can be cleaned with commercial solutions, however they often are not as effective after they have been cleaned. A better option is to simply remove and replace the large filters every two months of use. Brush the fins of the outside unit that are located behind the filters and remove all debris and dust either by blowing with compressed air or using a shop vacuum. Always keep the area around the outside unit free from long grass, bushes or vines that may obstruct air flow or add debris into the unit or filter.