Picking out the correct 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 part in keeping its system working safely, efficiently and for a long time.
An overused furnace filter loses its effectiveness, enabling potentially harmful particles to move through your home. It also slows airflow, which can damage your furnace and reduce its life span.
Making sure your furnace uses a clean filter that is appropriate for your needs is not merely about keeping your furnace working efficiently. It’s also about creating good indoor air quality for your residence.
The quality of the air your family breathes is important to the HVAC pros at Better Air. We've long worked with an eye on enhancing indoor air quality in Dundas and Northfield. Here, we’ve answered common questions about HVAC filters, including that particularly tricky question of what direction do you point a filter in your furnace or air conditioner?
When to Replace the Air Filter in Your Furnace
Experts stress it's critical to replace dirty air filters in a furnace or air conditioner routinely. Dirty filters cause the system to worker harder than it should because it takes extra effort to force air through the plugged-up filter.
Officials suggest examining your furnace filter every month and replacing it if it’s dirty. You’ll know if it is dirty because it will coated with dirt or dust. People who have pets that shed will likely have to replace their furnace air filter more often, because a quality 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 commonly found in the return air duct or blower compartment before the return air reaches the furnace. This is so air flowing into the system is filtered before it goes through the furnace components and is heated.
Depending on the furnace brand, the filter may be found on the right, left, bottom or in some cases, on the inside of the furnace. It's generally housed in a slot, frame or cabinet for simple access and replacement. Always refer to your furnace's owner manual for important information regarding filter location of the furnace in your home.
Is My Furnace Filter Just a Type of Air Filter?
The simple answer is, yes. In HVAC, a furnace filter and an air filter or air conditioning filter are essentially the same thing. While they might be called different things based on the current season— warm or chilly months—they are all filters that clean the air in your HVAC system.
They each get rid of dust, allergens, bacteria and other contaminants from the air that is drawn into the furnace and air conditioning system, ensuring the air circulating throughout your home is clean and safe.
What Are MERV Ratings and What MERV Rating Should I Have?
Once you find your old furnace filter and decide when it should be replaced, it’s time to choose a replacement. That means deciding on the level of filtration that you need. One way to do that is by picking 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 contaminants. The rating scale ranges from 1 to 20, with bigger numbers indicating enhanced capabilities to filter small particles.
Experts say a filter with a MERV rating between 8 and 13 offers an ideal balance between having good indoor air quality without needlessly restricting airflow. However, people with certain health conditions may need a a higher MERV rating.
How to Place the Air Filter in a Furnace or Air Conditioning System
Putting an air filter in a furnace or air conditioner the proper way is necessary for the efficient operation of the unit. 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 in the direction of the furnace or air conditioner, which is the direction of the airflow. If you're unsure about the airflow direction, remember that air always moves from the return duct and then to the heat or cooling source. Therefore, be sure that the arrow points toward the furnace or air conditioning unit.
Many people struggle with which direction to install their system's air filter. To help remember, consider taking a picture with your cell phone after the filter has been correctly 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 perfect time to ask about this is during a scheduled furnace maintenance visit.
How to Change a Furnace Air Filter
Changing the filter on your furnace or air conditioner is an easy process. Here is a step-by-step list of how to take out a dirty air filter and swap it for a new one:
- Turn off your furnace: Make sure to turn off your furnace before beginning 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 new filter to point similarly.
- Slide out the old filter: Be mindful not to knock out any dust or dirt.
- Note the date: Write down the date you changed filters on the new filter's frame. This will make it easier to keep track of when it's time for the next change.
- Slide in 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 old filter you are replacing.
- 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 replacement filter is safely in place, you can turn your furnace back on.
Can a Dirty Air Filter Cause a Furnace Not to Work?
The short answer is, yes, a dirty air filter can cause a furnace to quit working or limit its lifespan. Changing your furnace or AC filter is one of the easiest things you can do to keep your system running correctly.