A question we often get at AC San Marcos is, “how often should I change my AC filters?”.

AC filters keep dust and debris out of the air in your home, as well as out of expensive AC equipment. Without AC filters, the HVAC tubing in your home would be covered with dust in just a few years and the air quality in your home would drop. Because of the volume of air that passes through a modern HVAC system (especially in the hot Texas summers), filters in our region do tend to clog quickly. Clogged filters means your system pushes less air–and works harder for each degree of temperature change. In other words, your system gets expensive to run.

Ready for the sad truth? Ideally, in our region, you should change your AC filters 3 or 4 times per year. The absolute most important time is March–the beginning of the AC season. The middle of the summer is another good time to change the filter. The lightest period of HVAC use is generally between November to March–one filter change at the beginning of this cycle will usually be enough.

But inspect the filters themselves. 1/4 of an inch of dust means it’s time to change the filter.