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How often should you change your furnace filters?
Updated
By Alyssa Chua
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. How often you replace your furnace filter truly depends on several factors, such as the type:
- 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 trap small particles, dust mites, dirt, mold, bacteria, pet hair, and other contaminants from entering your air conditioner. 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).
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5 signs it's time to replace your furnace filters.
You may be unaware when your filter needs changing. Watch out for the following signs that tell you 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 in 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 air filter is filled with dirt and debris, the air won’t be able to pass through properly. If you notice that your house's temperature seems to be warmer than usual or that air isn’t flowing through your filter, it could be blocked.
4. Your home seems dirtier than usual.
Clogged air vents mean your air filter cannot clean your air properly. 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 above signs (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 instructions 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. Install the new filter with the airflow direction arrows pointing in the same direction as the filter you just removed.
Step 6: Replace the door or cover.
Return the blower cabinet door or access panel cover.
Step 7: Restore the power.
Switch the furnace on again and see what happens. If you installed your filter the right way, it should work well.
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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 the ones 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 their customer reviews, request price quotes, and schedule a service appointment.