Just like changing the oil in your car, your HVAC air filter requires changing on a regular basis – it is 100% required maintenance. We simply can’t stress enough as to how important this is.
Although this may sound like overkill, you should check your filter every month. This is particularly true during the heavy use months, which are usually the summer and winter months for the vast majority of folks in the United States, Canada and Europe. If your air filter looks dirty, change it right then and there. Don’t try and pinch pennies. At the very minimum, however, you need to change your air filter every 3 months.