Choosing the proper furnace filter and changing it when it gets dirty is as important to your HVAC system as changing the oil is to your car. Each plays a critical role in keeping its system running safely, efficiently and for a long time.
A dirty furnace filter loses its effectiveness, allowing potentially harmful particles to circulate through your home. It also restricts airflow, which can damage your furnace and reduce its life span.
Making sure your furnace uses a clean filter that is suitable for your needs is not just about keeping your furnace operating efficiently. It’s also about providing excellent indoor air quality for your residence.
The quality of the air your family breathes is important to the heating pros at Bigfoot Mechanical. We've long worked with an eye on improving indoor air quality in Spokane. Here, we’ve answered frequent questions about HVAC filters, including that especially tricky question of what direction do you point a filter in your furnace or air conditioner?
How Often to Replace the Air Filter in a Furnace
Experts stress it's important to replace dirty air filters in a furnace or air conditioner periodically. Dirty filters cause the system to worker harder than it should because it takes more energy to pull air through the plugged-up filter.
Officials advise examining your furnace filter monthly and replacing it if it’s dirty. You’ll know if it is dirty because it will coated with dirt or dust. Those who have pets will likely need to replace their furnace air filter more often, because an effective air filter will trap pet hair circulating in a home.
Where Is the Air Filter in My Furnace?
In general, a furnace air filter is usually installed in the return air duct or blower compartment before the return air gets to the furnace. This makes sure air being pulled into the system is filtered before it moves through the furnace components and is heated.
Depending on the furnace brand, the filter may be located on the right, left, bottom or in some cases, inside the furnace. It's generally housed inside of a slot, frame or cabinet for easy access and replacement. Always refer to your furnace's owner manual for important information concerning filter location of your furnace.
Is a Furnace Filter the Same as an Air Filter?
The straightforward answer is, yes. In HVAC, a furnace filter and an air filter or AC filter are essentially identical. While people may call them different things based on the current season— warm or chilly months—they are all filters that clean the air in your home.
They each remove dust, allergens, bacteria and other airborne debris from the air that is drawn into the furnace and air conditioning system, making sure the air circulating throughout your home is clean and safe.
What Is the MERV Rating System and What Rating Is Best for Me?
Once you track down your old furnace filter and figure out when it should be replaced, it’s time to select a replacement. That means deciding on the level of filtration that you need. One way to do that is by selecting an appropriate MERV rating for your needs.
MERV is an abbreviation for Minimum Efficiency Reporting Values. The MERV rating measures the effectiveness of air filters at trapping airborne molecules. The rating scale ranges from 1 to 20, with bigger numbers indicating a greater ability to filter smaller particles.
Experts say a filter with a MERV rating between 8 and 13 offers a good balance between having good indoor air quality without overly restricting airflow. However, people with specific health conditions may need to use a filter with a higher MERV rating.
How to Place the Air Filter in a Furnace or AC Unit
Positioning an air filter in a furnace or air conditioner correctly is crucial for the efficient operation of the system. Air filters are designed to be installed in a certain direction, indicated by an arrow located on the side of the filter frame. The filter should be placed in the unit with this arrow pointing at the furnace or AC, which is the direction of the airflow. If you're doubtful about the airflow direction, remember that air always moves from the return duct towards the heat or cooling source. Therefore, be sure that the arrow points at the furnace or air conditioner.
Many people are confused by which direction to point their system's air filter. To help remember, consider snapping a quick photo with your cell phone after the filter has been properly installed by a professional. Or, you also could ask a technician to use a marker to write on the outside of your furnace which direction the filter should go. A handy time to inquire about this is during a regular furnace maintenance appointment.
How to Replace Your Furnace Air Filter
Switching out the filter on your furnace or AC is an easy process. Here is a step-by-step breakdown of how to remove a dirty air filter and swap it for a new one:
- Turn off your furnace: Make sure to turn off your furnace before starting up the process.
- Look for the furnace filter: Typically, the filter is positioned within the furnace or in the air return vent. Make a mental note or write down which direction the arrow points on the filter, because you’ll want the arrow on the clean filter to point in the same direction.
- Take out the old filter: Be diligent not to knock out any dust or debris.
- Document the date: Write down the date you changed filters on the new filter's frame. This will help you keep track of when it's time for you to change it again.
- Insert new filter: Put in the new filter with the arrow pointing in the direction of the furnace, which is the direction of airflow and should be the same direction the arrow pointed on the dirty filter you just removed.
- Secure the filter: Make sure the new filter fits securely and close any latches or clips that lock it in place.
- Turn on your furnace: Once the clean filter is safely installed, you can turn your furnace back on.
Will a Dirty Air Filter Damage My Furnace?
The short answer is, yes, a dirty air filter can cause a furnace to quit working or limit its lifespan. Changing your furnace or air conditioning filter is one of the simplest things you can do to keep your system working efficiently.
