Choosing the ideal 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 critical function in keeping its system operating safely, efficiently and for a long time.
A dirty furnace filter loses its effectiveness, permitting potentially harmful particles to circulate through your home. It also limits airflow, which can damage your furnace and reduce its life span.
Ensuring 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 delivering healthy indoor air quality for your residence.
Your health is important to the heating and cooling specialists at Herman Allen Plumbing, Heating & Cooling. We've long focused on improving indoor air quality in Greater Richmond. 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?
When to Replace the Air Filter in Your Furnace
It is critical to replace dirty air filters in a furnace or air conditioner regularly. Dirty filters cause the system to worker harder than it should because it takes more energy to move air through the plugged-up filter.
Officials recommend inspecting 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 very likely have to replace their furnace air filter more often, because a good air filter will trap pet hair circulating in a home.
How to Find the Furnace's Air Filter
In general, a furnace air filter is usually located in the return air duct or blower compartment before the return air goes back into the furnace. This makes sure air entering 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, on the inside of the furnace. It's typically housed within a slot, frame or cabinet for simple access and replacement. Always refer to your furnace's owner manual for facts regarding filter location of your furnace.
Is My Furnace Filter Just a Type of Air Filter?
The straightforward answer is, yes. In HVAC, a furnace filter and an air filter or AC filter are effectively 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 residence.
They each eliminate dust, allergens, bacteria and other particulates from the air that is drawn into the furnace and air conditioning system, ensuring the air flowing through your home is clean and safe.
What Are MERV Ratings and What Rating Is Best for Me?
Once you track down your old furnace filter and determine when it should be changed, it’s time to pick a replacement. That means picking the level of filtration that you need. One approach to this is by choosing an appropriate MERV rating for your needs.
MERV stands for Minimum Efficiency Reporting Values. The MERV rating indicates 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 an ideal balance between having healthy indoor air quality without overly restricting airflow. However, people with certain health conditions may need a a higher MERV rating.
Where to Insert the Air Filter in a Furnace or AC Unit
Positioning an air filter in a furnace or air conditioner properly is important for the efficient operation of the unit. Air filters are supposed to face a specific direction, indicated by an arrow written 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 not sure about the airflow direction, remember that air always moves from the return duct towards the heat or cooling source. Therefore, make sure the arrow points toward the furnace or air conditioner.
Many people struggle with which direction to point their air filter. To help remember, consider taking a picture with your cell 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 point. A handy time to do this is during a regular furnace maintenance call.
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 list of how to take out a dirty air filter and replace it with a new one:
- Turn off your furnace: Be sure to turn off your furnace before starting up the process.
- Locate the furnace filter: Typically, the filter is found in the furnace or in the air return vent. Make note of which direction the arrow points on the filter, because you’ll want the arrow on the new filter to point the same way.
- Remove the old filter: Be careful not to knock out any dust or debris.
- Note 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 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 the old filter you are replacing.
- Secure the filter: Make sure the new filter fits nicely and close any latches or clips that hold it in the unit.
- Turn on your furnace: Once the replacement filter is completely in place, you can turn your furnace back on.
Can a Dirty Air Filter Cause Problems for a Furnace?
The shortest answer is, yes, a dirty air filter can cause a furnace to quit working or shorten its lifespan. Changing your furnace or AC filter is one of the easiest things you can do to keep your system operating efficiently.