One way to prevent unnecessary damage to your air conditioner is to change the filter on schedule. If you forget and the filter gets caked with dust, your air conditioner struggles to work, and it can get dusty and grimy inside. This might cause your AC to ice over or shut down. Changing the filter once a month or as often as instructed by the filter or AC manufacturer is important, and so is choosing the right filter. Here's how to buy a new filter for your central AC.
Get The Right Size
Look in the AC manual for the dimensions of the filter to buy. If you don't have your manual, look at the filter you have in there now for dimensions printed on the filter. You could also measure the filter opening. If you get the reading from the filter already in your AC, be sure the filter has a snug fit. A filter that's too small and has gaps around the side will let dust and other tiny debris inside the air handler and that can lead to problems that cause your AC to break down. The main purpose of an air conditioner filter is to keep dirt and dust out of the air handler, so it needs to be the right size.
Buy Flat Or Pleated
There are several air conditioner filters you can choose from, but a common one is the flat fiberglass filter you can buy in many places. You might even see this type of filter in your grocery store. It's easy to find and is cheap, so you may want to stock up on some of these to always have spare filters on hand. These usually need to be replaced about once a month, but some filters, such as pleated filters, can last longer than that. Pleated filters have more surface area than the flat filters due to the pleats, so they can last longer, and they may even be more effective at removing particles from the air. These may be made out of cotton rather than fiberglass, and they'll usually cost more.
Choose The MERV Rating
The MERV rating of a filter lets you know how well the filter can trap small particles like dust and pollen. The higher the rating, the better the filter is at filtering the air that's forced through it as the air goes in the air handler. You don't necessarily want to buy a filter with the highest rating you see because that might harm your HVAC. Instead, refer to your manual to find the highest MERV rating for your furnace. If you have allergies and want your air to be filtered as well as possible, then talk to your HVAC contractor call about your options for purifying the air.
If you have any questions, speak to an air conditioning professional.