The Basics on Air Filters


Changing the air filter on your HVAC system is one of the easiest yet most essential maintenance procedures that you can do on your own. While most homeowners are aware of this, few are comfortable enough to attempt to change them out on their own. During peak HVAC seasons (summer and winter), it is important that the air filter is changed out, or cleaned, at least once a month. This makes it all the more vital that homeowners educate themselves on the basics and the kind of filter that works best with their system.

There are three factors that you’ll want to consider before buying a new filter, and we’ve outlined them for you.

  1. SIZE – The size of the filter should be the easiest part of this equation, but filters come in various lengths and thicknesses. If you have recently purchased a home with an HVAC system, it should be simple enough to remove the filter and use it as a reference for a new one. But make sure that the current filter truly fits the space. Air filters work best when they fit tightly into their compartment. If you see gaps around the frame, or if the filter fits loosely, then it’s the wrong size. Most (not all) modern HVACs have a 1-inch space for the filter. Make sure to check your system’s requirements and get a size that fits securely into the compartment.
  2. TYPE – There are many different types of home air filters on the market. Like any product, some brands are better than others. Some designs need to be changed out every few months in order to remain effective while others are washable and only need to be replaced every six to eight years. The kind you use will depend on several factors, including the annual usage of your HVAC and the basic size requirements. Your HVAC technician will be able to recommend the best type of filter for your system, but it’s important to know the basic options if you ever need to replace a filter on your own.
    • Fiberglass filter – This is the most common type of air filter and also the most inexpensive. It is composed of layered fiberglass fibers supported by a metal grating. These are designed to catch large particles including dust and lint but aren’t as efficient at catching airborne toxins and allergens.
    • Polyester/pleated filter – Similar in design to fiberglass, but more effective in catching smaller particles. This design has a stronger resistance to airflow and typically need to be changed more often than the fiberglass models. This type of filter is also a bit more expensive.
    • Electrostatic filter – This design has electrically charged fibers that can collect both large and small particles. It is very effective at reducing airborne allergens and recommended for people who have severe allergies.
    • Reusable electrostatic filter – This is very similar to the disposable version, but doesn’t collect as many particles. It is considered more “green” because it is washable and lasts about six to eight years. Washable filters need to be dried thoroughly before they are used again to prevent mold.
  3. MERV RATING – Most air filters are given a performance rating issued from the Environmental Protection Agency (EPA). Called the Minimum Efficiency Reporting Value (or MERV), this system rates the effectiveness on the filter on a scale of 1 to 16. The higher the MERV rating, the more efficient it is in collecting particles. It is recommended that a household filter should have a minimum MERV rating of 7. Higher isn’t necessarily better for home HVAC filters. MERV-rated brands that have a rating of 7 – 12 effectively remove airborne contaminants while anything rated higher is typically found in hospitals and businesses. More on the MERV Rating

The ideal filter for your HVAC will both securely fit the system and help keep your family healthy. If you are experiencing problems with your indoor air quality, all that you may need is a higher MERV rating on your filter. If you have any questions or concerns regarding your current filter, give Service Legends a call today. We can properly evaluate your system and help with any decisions regarding the type of filter that would work best for your household.

Thank you for making Service Legends the #1 provider of residential heating and air conditioning in the Des Moines area. A live and friendly customer care representative is ready to take your call 24/7 at 515-COMFORT (515.266.3678).

515-657-6634Request Appointment Online