Selecting 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 role in keeping its system operating safely, efficiently and for a long time.
A clogged furnace filter loses its effectiveness, permitting potentially harmful particles to flow through your home. It also restricts airflow, which can damage your furnace and shorten its life span.
Making sure your furnace uses a clean filter that is ideal for your needs is not only about keeping your furnace operating efficiently. It’s also about providing good indoor air quality for your home.
The quality of the air your family breathes is important to the heating and cooling professionals at Arizona Comfort Systems. We've long focused on enhancing indoor air quality in Sierra Vista. Here, we’ve answered common 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 vital to replace dirty air filters in a furnace or air conditioner regularly. Dirt-clogged filters cause the system to worker harder than it should because it takes extra effort to pull air through the plugged-up filter.
Officials recommend inspecting your furnace filter monthly and replacing it if it’s dirty. You’ll know if your filter needs changing because it will be gray or black from dirt or dust. People who have pets that shed will probably want to replace their furnace air filter more often, because a quality air filter will trap pet hair circulating in a home.
Locating Your Furnace's Air Filter
In general, a furnace air filter is commonly installed in the return air duct or blower compartment before the return air reaches the furnace. This ensures 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 positioned on the right, left, bottom or in some cases, within the furnace. It's generally housed inside of a slot, frame or cabinet for simple access and replacement. Always refer to your furnace's owner manual for facts concerning 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. While people might refer to them differently based on the current season— hot or cold—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, 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 locate your old furnace filter and figure out when it should be changed, it’s time to pick a replacement. That means picking 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 calculates the effectiveness of air filters at trapping airborne contaminants. The rating scale ranges from 1 to 20, with bigger numbers indicating the power to filter small particles.
Experts say a filter with a MERV rating between 8 and 13 offers an appropriate balance between having healthy indoor air quality without unnecessarily restricting airflow. However, people with certain health conditions might need to use a filter with a higher MERV rating.
How to Place the Air Filter in a Furnace or AC Unit
Installing an air filter in a furnace or air conditioner correctly is necessary for the efficient operation of the system. Air filters are designed to be installed in a particular direction, indicated by an arrow printed on the side of the filter frame. The filter should be installed with this arrow pointing in the direction of the furnace or air conditioner, which is the direction of the airflow. If you're doubtful 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 in the direction of the furnace or air conditioning unit.
Many people are confused by which direction to install an air filter. To help remember, consider taking a picture with your mobile 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 handy time to do this is during a routine furnace maintenance visit.
Changing Your Furnace's Air Filter
Switching out the filter on your furnace or AC is an easy process. Here is a step-by-step rundown of how to remove a dirty air filter and exchange it for a new one:
- Turn off your furnace: Make a point to turn off your furnace before beginning the process.
- Look for the furnace filter: Typically, the filter is positioned in the furnace or in the air return vent. Take note of which direction the arrow points on the filter, because you’ll want the arrow on the new filter to point in the same direction.
- Slide out the old filter: Be mindful not to knock out any dust or particles.
- Record the date: Write down the date you replaced the filter on the new filter's frame. This will make it easier to keep track of when it's time for you to change it again.
- 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 dirty filter you just removed.
- Secure the filter: Make sure the new filter fits securely and close any latches or clips that secure it in the unit.
- Turn on your furnace: Once the clean filter is safely installed, you can turn your furnace back on.
Will a Dirty Air Filter Cause a Furnace Not to Work?
The simple answer is, yes, a dirty air filter can cause a furnace to quit working or limit its lifespan. Changing your furnace or air conditioner filter is one of the easiest things you can do to keep your system working correctly.