How to Change the Air Filter in Your Furnace

Of all the ways to protect and maintain your Seattle, WA home, changing your furnace filter is likely the easiest. It’s also among the most important. This component removes dirt, hair, lint, dander, and many other particulates before they enter your heating equipment and negatively impact its performance. Regular filter changes will improve your indoor air quality (IAQ) and promote furnace safety. They’ll also extend the lifespan of your heater. The following is everything you need to know about performing furnace filter changes.

Refer to the Instructions of Your Furnace Manufacturer

While most furnaces and furnace filters are fairly the same, each model has its own nuances and needs. If you’ve never changed the filter on your furnace before, take a minute to look at your owner’s manual. This should provide a clear diagram of the furnace, its filter location, and other details to help you along. If you still have questions after reading your manual, call your furnace manufacturer or your HVAC installer. Having a knowledgeable party guide you through this process is far better than installing your new filter incorrectly.

Choose the Right Filter Type and Stock Up

Air filters with accumulated debris place a tremendous amount of stress on heating equipment. If your furnace filter is excessively dirty, your heater will have to work harder than normal to move air through this component. In general, homeowners are advised to change their furnace filters every 30 to 60 days. However, you should visually inspect your air filter monthly. This way, if changes in your indoor air quality result in dramatic increases in filter debris, you can swap your filter out before problems arise.

During the winter months when heaters are running non-stop or nearly non-stop, it helps to have an extra filter. Your owner’s manual, your HVAC installer, or your furnace manufacturer can tell you the exact filter type to use.

Even if you’ve been able to perform furnace filter changes just once every three months in the past, check your filter every month of winter just in case. As heating equipment ages, it tends to collect more dust and other debris than it did in its younger years. As your furnace nears the end of its lifespan, you’ll likely find it necessary to increase the frequency of filter changes. Moreover, it’s always better to have more filters than you actually require for winter than not enough.

Opt for a Higher-Rated Furnace Filter for Improved Indoor Air Quality

Every furnace filter sold in the United States has a maximum efficiency reporting value (MERV) rating. MERV ratings provide insight into the different airborne particulates that a filter can collect with lower MERV ratings applied to filters that only pick up large-sized contaminants. The higher that a filter’s MERV rating is, the more allergens and other pollutants it can extract from your indoor air.

Standard furnace filters have MERV ratings of eight. Most of these components capture about 90% of airborne particulates, including:

  • Dust
  • Lint
  • Pollen
  • Dander
  • Dust mites

Some standard filters are even known to pick up mold spores.

Although the performance of a standard furnace filter sounds pretty impressive, these options are primarily designed to protect heating equipment rather than humans. If you want your filter to make noticeable improvements to your IAQ, you should upgrade to an option that has a MERV rating of at least 11. Filters rated 11 or higher can extract smog, smoke, and other toxins that are known to exacerbate the symptoms of allergies and asthma.

However, keep in mind that increasing your filter’s MERV rating by too much can also cause HVAC system stress. Much like build-ups of debris, tighter, smaller filter mesh will inhibit airflow. In fact, filters that have MERV ratings of 13 or higher often require special HVAC system modifications to ensure optimum heater performance. Paying a bit more to upgrade a standard air filter will boost your IAQ without negatively impacting your furnace. For major filter upgrades, it’s best to first consult with a licensed HVAC company.

Turn Your Furnace Off

Operating your furnace absent of a filter is always a bad decision. Without a filter, your heater will draw in substantial amounts of dirt and other debris within a very limited amount of time. To prevent this, turn your furnace completely off before getting started. Simply toggle your thermostat into the “OFF” position.

Next, look for the access door. This will be a small, swinging or sliding door panel at the front of your furnace that you can remove or open to access the unit’s interior. The filter will be near the blower chamber’s entrance or right by the return air duct. If you don’t spot the filter immediately, search for the vents where air is drawn into the system.

Gently lift your old filter out while paying careful attention to its orientation. You should install your filter in the exact same way. When removing an old, debris-covered filter, take care to avoid knocking trapped particulates loose. If you have a hard time sliding the old filter out, check for a locking mechanism that might be blocking its way. To release a filter in a furnace that has a locking mechanism, slide the lock out of position.

If you’re simply inspecting your furnace filter to determine whether or not it’s time to replace it, hold it up to the light. You should be able to see a small amount of light shining through it. If light cannot penetrate your filter’s mesh, you can safely assume that air has a hard time moving through it, too.

Make Sure Your New Filter Has a Secure Fit

Slide your new furnace filter in. It should have a secure, stable fit. If you used a reliable source to determine the correct filter size, you shouldn’t have any problems. Having an undersized furnace filter installed is just as bad as not having one at all. When your heater is turned back on and this component is subjected to a strong flow of air, it may be dislodged entirely.

Changing a Furnace Filter in Pre-Existing Construction

If you’ve recently purchased pre-existing construction, you cannot assume that the previous homeowner installed the furnace filter correctly or that they chose the right filter type and size. In fact, you shouldn’t assume that they’ve installed a filter at all. Before turning your heater on, make sure that there’s a clean and properly fitted filter in place. You should also compare the orientation of the existing filter with the filter images that are in your owner’s manual.

We make it easy for residents of Seattle, WA to stay on top of basic furnace maintenance. We offer heating, cooling, electrical, and indoor air quality services. We also provide water heaters, gas fireplaces, and whole-house air purification equipment. To find out about our preventative maintenance plans or to schedule an appointment, contact Black Lion Heating & Air Conditioning now.