For optimum performance, you should change your filter monthly. Replacing your filter every other month is also acceptable as long as you do not have pets, excessive smoke or anyone with asthma or breathing sensitivities in your home or building. While our filters are highly energy efficient, they are created to capture far more debris than a standard filter. Because of this, extended use can negatively impact the lifespan of your HVAC units as well as provide a less than premium breathing experience.