Every home is different as some people change their filters every thirty days and others wait as long as ninety days. How often the filters are changed depends on the home’s environment and the quality of filter being used. Homes that are in more dusty locations and those that have pets will require more filter changes. Also, the better-quality filters will need to be changed more often as they are stopping more debris and smaller particles. If you or someone in your family has asthma or allergies, this usually causes the time frame to change the filter to narrow as well. When in doubt, change the filter. They are relatively-inexpensive and could save you from having to make an expensive repair in the future. Call Absolute Comfort, Inc. to discuss your options on better filters and/or, air purification.