A good rule of thumb when it comes to how often home or business owners should change their HVAC system air filters is 30-90 days, depending on the size of your house or place of business, environmental conditions and the type of air filter you choose to use.
For instance, whereas fiberglass HVAC air filters are inexpensive and the least effective choice, HEPA filters are the most expensive, most effective type of air filters and the best choice for those who suffer from respiratory issues such as asthma or allergies. Pleated filters tend to be more middle of the road as far as cost and efficiency.
If you live in an area with a lot of pollen or a place where you can smell prescribed burns from time to time, more frequent air filter changes will be required. If it can get dry or dusty around your house or you have pets, your HVAC air filter will also require more changes. The larger your home or business is, the more air and dust circulates, also necessitating more frequent air filter changes.
If you experience any of the environmental challenges listed above, you may want to change your air filter every 30-45 days. At the very least, it is a good idea to visually check your HVAC air filter monthly. If you cannot see light through your air filter when you hold it up to a light source, it is time for a change.