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 clogged 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 sure your furnace uses a clean filter that is appropriate for your needs is not just about keeping your furnace running efficiently. It’s also about providing healthy indoor air quality for your home.
Your health is important to the HVAC professionals at Kilbourne Heating & AC. We've long focused on bettering indoor air quality in Delray Beach. Here, we’ve answered frequent questions about HVAC filters, including that particularly 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 is 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 work to pull air through the plugged-up filter.
Officials recommend checking your furnace filter monthly and replacing it if it’s dirty. You’ll know if the filter needs to be changed because it will filled with dirt or dust. Homeowners who have pets will probably need 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 usually 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 passes through the furnace components and is heated.
Depending on the type of furnace, the filter may be positioned on the right, left, bottom or in some cases, on the inside of the furnace. It's typically housed in a slot, frame or cabinet for simple access and replacement. Always refer to your furnace's owner manual for important information about filter location of your particular brand and model of furnace.
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 conditioner filter are basically the same. While they might be called different things based on the current season— hot or cold—they are all filters that clean the air in your residence.
They each remove dust, allergens, bacteria and other contaminants from the air that is drawn into the furnace and air conditioning system, ensuring the air distributed throughout your home is clean and safe.
What Is a MERV Rating and What MERV Rating Do I Need?
Once you track down your old furnace filter and decide when it should be changed, it’s time to select a replacement. That means determining the level of filtration that you need. One way to do that is by choosing an appropriate MERV rating for your needs.
MERV stands for Minimum Efficiency Reporting Values. The MERV rating measures the effectiveness of air filters at trapping airborne particles. The rating scale ranges from 1 to 20, with higher 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 overly restricting airflow. However, people with some health conditions might need to purchase a filters with a higher MERV rating.
Which Way to Put the Air Filter in a Furnace or Air Conditioner
Positioning an air filter in a furnace or air conditioner the proper way is crucial for the efficient operation of the unit. Air filters are supposed to face a specific direction, indicated by an arrow printed 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 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 in the direction of the furnace or AC.
Many people have difficulty remembering which direction to point their air filter. To help remember, consider snapping a quick photo with your cellular 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 be installed. A handy time to do this is during a routine 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 breakdown of how to retreive a dirty air filter and swap it for a new one:
- 1. Turn off your furnace: Make a point to switch off your furnace before beginning the process.
- Locate 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 replacement filter to point similarly.
- Slide out the old filter: Be careful not to knock out any dust or dirt.
- Document the date: Write down the date of replacement on the new filter's frame. This will make it easier to keep track of when it's time for the next change.
- Insert new filter: Put in the new filter with the arrow pointing toward the furnace, which is the direction of airflow and should be the same direction the arrow pointed on your last filter.
- Secure the filter: Make sure the new filter fits correctly and close any latches or clips that lock it in place.
- Turn on your furnace: Once the replacement filter is properly installed, you can turn your furnace back on.
Will 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 decrease its lifespan. Changing your furnace or air conditioning filter is one of the simplest things you can do to keep your system operating efficiently.