If you’ve never swapped out a furnace filter before, it’s really not as tricky as it might seem. I’ve walked plenty of people through this simple job, and it only takes a few minutes — you won’t need any tools whatsoever.
Start by turning your furnace off at the thermostat. Just set it to OFF so the fan doesn’t start up while you’re handling the filter. This keeps dust from getting blown around your whole house.
Now find where the filter is located. Most furnaces have it in a sliding tray right on the unit. Other times it’s behind a large return vent on the wall or ceiling, usually under a small plastic or metal cover that pops right open.
Carefully pull out the old filter. It’ll be dusty, likely dark and clogged — that’s just how it looks after catching all that debris. Before you throw it away, note the size printed on the side.A 14×25×1 filter is a really common size, but you still have to use whatever size your furnace is designed for. If it’s even a little off, it won’t sit tight and air will leak around it.
Don’t forget the little arrow on the filter either. That arrow shows which way the air runs in your system, so just point it toward the furnace, not into your house.
Take the new filter out of its wrapper, line up that arrow the right way, and slide it in nice and easy. Don’t cram it or bend it — just set it in straight so it fits tight and stays in place.
Put the cover back on if you had one, then turn the thermostat back to HEAT or AUTO. That’s it — you’re finished.
If you want better air quality and less dust in your home, go with a best furnace filter that fits your system. It helps the furnace run more efficiently too, which can save you a little on energy bills.
FAQ
How often should I change my furnace filter?
Every 1–3 months in a normal home. If you have pets or kids, or someone with allergies, I always recommend changing it monthly.
Do I have to use a 14 x 25 x 1 furnace filter?
Only if that’s the size on your old filter. Using the wrong size just lets unfiltered air pass through.
What if I put the furnace filter in backward?
It blocks airflow and makes your furnace work too hard. Just follow the arrow and you won’t have that problem.
What makes the best furnace filter?
One that traps dust and pollen without slowing down air too much. You don’t need the fanciest one — just one that fits well.
Can I run my furnace without a furnace air filter?
Definitely not. Dust will build up inside the furnace and can break parts, which gets expensive fast.
