What It Means
An HVAC filter sits in a home's central air conditioner, furnace or heat pumpHeat pumpAn electric system that heats and cools a home by moving heat: from the outdoor air into the house in winter, and out of the house in summer. See more and catches dust and other particles from the air moving through the system. As it clogs, air flows through more slowly and the equipment works harder, which ENERGY STAR says wastes energy. Keeping it clean also protects the system from a buildup of dirt that DOE says can make it fail early. Filters are graded by a MERVMERV ratingMinimum Efficiency Reporting Value: a number showing how well an air filter traps particles 0.3 to 10 microns in size, where a higher number catches more small ones. See more number that shows how well they trap particles.
Try It: Is It Time to Change Your Filter?
Answer three questions about the filter in your system. The advice comes from ENERGY STAR and the Department of Energy.
Change it now
Check it monthly and expect to change it sooner
Fine for now, check again next month
ENERGY STAR says a filter that looks dirty after a month should be changed.
Three months is ENERGY STAR's outside limit, even when the filter looks clean.
DOE says pets, dust and constant use can mean more frequent changes.
Months left before the 3-month limit:
How It Sounds at Home
- "The furnace filter is gray again already."
- "Grab a new AC filter while you're at the store."
- "With two dogs, we swap ours every month."
The Breakdown
How often, per ENERGY STAR, DOE and EPA
| Situation | What to do | Source |
|---|---|---|
| Every month | Check the filter | ENERGY STAR |
| Winter and summer, the heavy-use months | Make the monthly check a must | ENERGY STAR |
| It looks dirty after a month | Change it | ENERGY STAR |
| However clean it looks | Change it at least every 3 months | ENERGY STAR |
| Cooling season, if you're not sure | Clean or replace it every month or two | DOE |
| Pets, dusty conditions or a system in constant use | Check and replace more often | DOE |
| Upgrading to a better filter | MERV 13, or the highest your fan and filter slot can take | EPA |
Getting the right replacement. Write down the dimensions of the filter that's in the slot now before you shop, and buy the same size. If you're thinking of moving up to a higher MERV, check your system's manual or ask an HVAC technician first.
Keeping on schedule. Buy two or three filters at once so a spare is waiting the day a check shows a dirty one. Write the date of each change on the new filter's frame or in your notes, so the next monthly check starts from a known date.
Good to Know
EPA says any higher-efficiency filter has to suit your existing ducted system, because a denser filter can hold back airflow. The same guidance says a MERV 13 filter works in most home systems as long as you replace it often. ENERGY STAR pairs these monthly checks with a professional tune-up every spring and fall.
FAQ
How often should I change my HVAC filter?
ENERGY STAR says to check it every month and change it whenever it looks dirty, and to change it at least every 3 months regardless. DOE suggests every month or two during the cooling season if you're unsure.
Do pets mean changing the filter more often?
They can. DOE says a system in a home with pets, dusty conditions or constant use may need its filter checked and replaced more often.
What happens if I don't change my air filter?
A dirty filter slows the air moving through the system, so it works harder and uses more energy, according to ENERGY STAR. DOE adds that dirt building up inside the equipment can make it fail early.
Do It in Buhata
Maintenance (Household X), Reminders
Set a monthly Reminder in Buhata to check the HVAC filter, and add "Change HVAC filter" to Maintenance in the Household X add-on on a 3-month schedule.
Open BuhataRelated Terms and Categories
- MERV rating
Minimum Efficiency Reporting Value: a number showing how well an air filter traps particles 0.3 to 10 microns in size, where a higher number catches more small ones.
- HVAC tune-up
A service visit where a qualified contractor checks, cleans and adjusts a heating or cooling system; ENERGY STAR advises one for cooling each spring and heating each fall.
- Furnace maintenance
The routine care a furnace needs: a monthly filter check, a yearly professional cleaning and inspection before heating season, and a working carbon monoxide alarm.
- Seasonal home maintenance
Home upkeep sorted by time of year, so each job lands when the weather suits it and before the system it protects is needed most.
Sources
ENERGY STAR, "Maintenance Checklist"; U.S. Department of Energy, "Air Conditioner Maintenance"; U.S. EPA, "What kind of filter should I use in my home HVAC system?"; U.S. EPA, "Guide to Air Cleaners in the Home"
- www.energystar.gov/saveathome/heating-cooling/maintenance-checklist
- www.energy.gov/energysaver/air-conditioner-maintenance?nrg_redirect=471658
- www.epa.gov/indoor-air-quality-iaq/what-kind-filter-should-i-use-my-home-hvac-system-help-protect-my-family
- www.epa.gov/indoor-air-quality-iaq/guide-air-cleaners-home
Last updated .