How often should I change my HVAC filter?
Last updated 12 October 2026
The short answer
Check it every month and change it when it is dirty. ENERGY STAR's advice is to inspect, clean or change the air filter in your central air conditioner, furnace or heat pump once a month. How long a particular filter lasts depends on the filter and the house; the packaging usually gives its rated life.
Why it matters
In ENERGY STAR's words: “A dirty filter can increase energy costs and damage your equipment, leading to early failure.”
How to check it
Find it
Usually behind a return-air grille in a wall or ceiling, or in a slot at the furnace or air handler.
Look at it
Pull it out and hold it up to a light. If the light barely comes through, change it.
Buy the right one
The size is printed on the frame. The arrow on the frame shows the airflow direction and points toward the unit.
While you are there: the condensate drain is part of the yearly check-up, and ENERGY STAR warns that “a plugged drain can cause water damage in the house and affect indoor humidity levels.”
What HavnOS schedules
HavnOS puts the filter changes for your heating and cooling on your calendar. If your filters run out sooner, or last longer, change the interval on the task and the dates follow.
Sources
Each source was read on 12 October 2026. Quotes are the source's own words.