Choosing the right furnace filter and changing it when it is dirty is as important to your HVAC system as changing the oil is to your car. Each plays a crucial function in keeping its system working safely, efficiently and for a long time.
An overused furnace filter loses its effectiveness, allowing potentially harmful particles to circulate through your home. It also slows airflow, which can damage your furnace and shorten its life span.
Making certain your furnace uses a clean filter that is appropriate for your needs is not merely about keeping your furnace operating efficiently. It’s also about delivering good indoor air quality for your home.
The health of your family is important to the heating and cooling pros at Temperature Doctors Heating & Cooling. We've long worked with an eye on improving indoor air quality in Rockford. 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
It's critical to replace dirty air filters in a furnace or air conditioner routinely. Soiled filters cause the system to worker harder than it should because it takes extra work to force air through the plugged-up filter.
Officials recommend examining your furnace filter monthly and replacing it if it’s dirty. You’ll know if it is dirty because it will be gray or black from dirt or dust. Homeowners who have pets that shed will probably have to replace their furnace air filter more often, because a good 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 located in the return air duct or blower compartment before the return air gets to the furnace. This ensures air entering the system is filtered before it goes through the furnace components and is heated.
Depending on the type of furnace, the filter may be located on the right, left, bottom or in some cases, within the furnace. It's usually housed inside of a slot, frame or cabinet for easy access and replacement. Always refer to your furnace's owner manual for important information about filter location of the furnace in your home.
Is a Furnace Filter the Same as an Air Filter?
The easy answer is, yes. In HVAC, a furnace filter and an air filter or air conditioning filter are essentially the same thing. While people may call them different things based on the current season— hot or cold—they are all filters that clean the air in your HVAC system.
They each remove dust, allergens, bacteria and other particulates from the air that is drawn into the furnace and air conditioning system, making certain the air distributed 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 changed, it’s time to pick a replacement. That means picking the level of filtration that you need. One method to do this is by choosing an appropriate MERV rating for your needs.
MERV stands for Minimum Efficiency Reporting Values. The MERV rating calculates the effectiveness of air filters at trapping airborne particles. 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 an appropriate balance between having good indoor air quality without unnecessarily restricting airflow. However, people with some health conditions could need to use a filter with a higher MERV rating.
How to Place the Air Filter in a Furnace or AC Unit
Putting an air filter in a furnace or air conditioner correctly is crucial for the efficient operation of the heating or cooling system. Air filters are supposed to face a particular direction, indicated by an arrow located on the side of the filter frame. The filter should be put in with this arrow pointing toward the furnace or air conditioner, which is the direction of the airflow. If you're not sure about the airflow direction, it may be helpful to remember that air always moves from the return duct to the heat or cooling source. Therefore, be sure that the arrow points at the furnace or air conditioner.
Many people struggle with which direction to point their system's air filter. To help remember, consider taking a quick picture with your mobile phone after the filter has been accurately 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 great time to inquire about this is during a regular furnace maintenance appointment.
How to Change a Furnace Air Filter
Changing the filter on your furnace or air conditioner is a simple process. Here is a step-by-step breakdown of how to take out a dirty air filter and exchange it for a new one:
- Turn off your furnace: Be sure to turn off your furnace before starting the process.
- Locate the furnace filter: Typically, the filter is found inside 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 the same way.
- Take out the old filter: Be careful not to knock out any dust or particles.
- Record 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 at 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 nicely and close any latches or clips that lock it in place.
- Turn on your furnace: Once the clean filter is properly installed, you can turn your furnace back on.
Will a Dirty Air Filter Cause Problems for a Furnace?
The simple answer is, yes, a dirty air filter can cause a furnace to stop working or shorten its lifespan. Changing your furnace or air conditioning filter is one of the easiest things you can do to keep your system running efficiently.