How often do I need to change my furnace filter?
Most furnace filters should be changed every 1–3 months, or monthly during heavy use or if you have pets or allergies. A dirty filter restricts airflow and reduces system efficiency.
Written by Paul Coen, Owner
How often do I need to change my furnace filter?
Most furnace filters should be changed every 1 to 3 months. If you run your system heavily, have pets, or deal with allergies, monthly changes are the safer bet — a dirty filter restricts airflow, forces your system to work harder, and reduces overall efficiency.
What changes the schedule
The "right" interval depends more on your household than a fixed rule. A thicker, higher-MERV filter may last longer than a thin one-inch filter, while homes with shedding pets, ongoing construction or renovation dust, or multiple allergy sufferers tend to need more frequent changes regardless of filter type.
Signs your filter needs changing sooner
- Visibly gray or clogged when held up to light
- Noticeably weaker airflow from your vents
- More dust settling around the house than usual
- Your system running longer cycles to reach the set temperature
Not sure what filter size or type your system needs? Our technicians can check it and set you up on the right replacement schedule — call LJ Refrigeration Co. at (480) 948-5004.