One of the most important things you can do to keep your air conditioner or heating system working a maximum efficiency is change your air filter. A dirty air conditioner filter can reduce equipment efficiency by twenty percent or more. Air conditioner filters should be changed every 3 to 6 months. Some contractors recommend every month but this is usually a bit extreme. Unless of course you suffer from allergies.

Every home is different and there are many factors that effect how long you should wait between filter changes. Wait too long and the efficiency of the equipment will deteriorate and operating costs go up. Change your filter too often and it's like throwing money away. Considering the cost of some air conditioner filters that could add up to a lot of money over time.

The more efficient your air filter is the more often you will have to change or clean it. For most applications pleated filters will do the job. These filters can have high efficiency ratings, as high as 60 percent depending on the manufacturer. Some manufacturers claim even higher efficiency ratings.

Generally, pleated air conditioner filters should be changed between 3 and 6 months, depending on how dusty your area is. Things like construction or living near dirt roads can make it necessary to change them more often.

If you require more efficient air filtration you may want an electrostatic, electronic or even a HEPA filter. The more efficient the filter is the more often it will have to be cleaned or replaced.

Electrostatic filters offer the greatest value. They cost 2 to 6 times more than an efficient disposable filter but are reusable. You simply rinse them with water and they are ready to use again.

Electronic filters will never become dirty enough to effect airflow. They just become inefficient and there ability to remove dust from the air diminishes. To clean these filters you have to remove the electronic cells and soak them in something like HVAC cleaner and then rinse them and let them dry.

The most efficient filters available are HEPA filters. These filters become plugged very quickly and must be checked often. These filters restrict air flow so much that they can cause problems with equipment operation if not maintained properly.

If you are using economy panel filters from your local hardware store and getting a pack of four for five or ten dollars, you are not doing yourself, your family or your air conditioning equipment any favours. When it comes to rating filters, these are at the bottom of the list.

These filters are so inadequate that you could probably keep one in your ac unit for a year before it would collect enough dust to effect its efficiency. Unfortunately most dust passes through these filters and builds up on the evaporator coil.