How often should you change your furnace filters?
By Alyssa Chua•Last updated Oct 3, 2023
Last updated Oct 3, 2023
Clean furnace filters mean better air quality for your home. With a fresher air filter, your HVAC system will run more efficiently, lowering energy bills. Ideally, change your filter every 90 days or so. However, some manufacturers may suggest changing it anywhere from every 30 days to every 9 months.
Factors that impact how often to change filters
How often you replace your furnace filter depends on several factors:
- The type of filter and MERV rating. Thicker, pleated filters can usually last longer than thinner filters.
- If you have pets. A home with pets means more hair and dander can clog the filter. You may need to change it more frequently.
- If someone has allergies. You may want to change it more often if someone in your household suffers from severe allergies or asthma.
- The climate. Are you dealing with high humidity? Wildfire smoke? You may need to change or clean your filters more often than usual.
- What your manufacturer recommends. Always follow your manufacturer's guidelines and cleaning/changing schedule for the best results. A good rule of thumb is to check your filters regularly. Visually inspect them for dirt, pet hair, and other debris to decide if it's time to replace or clean them.
Why is it important to replace your filters?
Furnace filters are designed to catch dust, dirt, pollen, mold spores, pet hair, and other contaminants before they circulate through your home or build up inside your HVAC system. As a result, your home’s air quality should improve, making it easier for you to breathe.
Frequently changing your furnace filters can also help extend your furnace's lifespan. If you don’t regularly clean your furnace's filter, it can become clogged and restrict airflow. An extremely dirty, clogged filter reduces indoor air quality and can make your HVAC system work less efficiently. It can also damage your heating and cooling system.
Installing a new furnace or HVAC system can get expensive. If you want your furnace to last a long time, take good care of the one you currently have. Start by doing the following:
- Changing the filter regularly
- Performing a deep clean of the entire unit
- Scheduling maintenance and repairs when needed
5 signs it's time to replace your furnace filters
You may not always know when your filter needs to be changed. Watch for these signs that your furnace filter is dirty or damaged:
1. Your filter is gray-colored, or you see a buildup of dust or dirt
If you inspect your filter and see it is no longer its original color or has a dusty, dirty buildup on the surface, it's time to change it.
2. Your heating and cooling bills are gradually increasing
Did you notice a sudden spike in your monthly energy bill? It could be that your furnace filter is dirty or damaged. Clogged filters restrict airflow, forcing your HVAC system to work harder and consume more energy.
3. You notice reduced airflow through your air vents
Once your filter fills with dirt and debris, air can't pass through it properly. If your rooms feel cooler than usual, take longer to heat up, or you feel weak airflow coming from your vents, your filter may be blocked.
4. Your home seems dirtier than usual
A clogged filter can't capture dust and dander, so it recirculates through your home instead of getting trapped. If you notice you're having to clean your home to get rid of dust and pet dander more often than usual, you may have a dirty furnace filter.
5. The air quality seems worse than it usually is
Is it getting harder to breathe? If you or the people in your home are suddenly having respiratory problems, check your filter. Mold, dust, dirt, and other contaminants could be stuck in your filter, making it hard to breathe.
How to change your furnace filters
If you notice any of the signs above, or you can't remember the last time you changed your filter, now is the time to take action.
As with any home project, always check your owner's manual for specific instructions on how to replace your filters. Or, you can follow this step-by-step guide for general guidance.
What you'll need
Be sure you have the following tools on hand before starting the project:
- Furnace filter replacement
- Screwdriver
- Sponge or cloth rag to clean reusable filters
When you’ve got all your tools on hand, it's time to change your filter.
Step 1: Turn off your furnace
You can either turn off the thermostat setting or cut off the power using the switch located on the furnace exterior.
Step 2: Locate the filter
The filter is usually found in the furnace’s blower compartment or ductwork leading to it.
Step 3: Open the door or panel to access the filter
Depending on where your filter is located, you will have to open the blower cabinet door or remove the duct-mounted access panel to access it. It’s best to have a screwdriver nearby in case you need to loosen screws to open the panel.
Step 4: Remove the current filter
Be careful when completing this step. If it’s been a long time since you last changed your filter, there may be a buildup of dust and dirt that can spill onto your clothes or floors.
If your filter is washable or reusable, check the label. Rinse it with water to remove all of the dust and dirt. Use a clean sponge or cloth rag to wipe away debris while rinsing it. Make sure it is completely dry before reinstalling it.
Remember that filters have lifespans. If your filter has exceeded its lifespan, you'll want to buy a new one instead of reinstalling the old one.
Step 5: Install the new filter
Note the airflow direction arrows printed on the side of the filter. These should point in the direction the air flows — toward the furnace and away from the return duct. If you're unsure, check your owner's manual rather than copying the old filter's position, in case it was installed backward.
Step 6: Replace the door or cover
Return the blower cabinet door or access panel cover.
Step 7: Restore the power
Switch the furnace back on and confirm warm air is coming from your vents. If airflow seems weak, double-check that the filter is seated properly and facing the right direction.
Skip DIY — hire a professional on Thumbtack
While changing or replacing your furnace air filter isn’t rocket science, you might feel more reassured if a professional handles the job. After all, they’re equipped with the tools and know-how. Plus, they can inspect your furnace for other issues you may not notice and make recommendations.
Need help finding the right pro for this job? Download the Thumbtack app to get started on your search. Compare top-rated HVAC technicians near you, read customer reviews, request price quotes, and schedule a service appointment.
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