Selecting the correct 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 vital role in keeping its system operating safely, efficiently and for a long time.
A clogged furnace filter loses its effectiveness, enabling potentially harmful particles to flow 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 suitable for your needs is not only about keeping your furnace operating efficiently. It’s also about providing healthy indoor air quality for your residence.
Your health is important to the heating pros at Kelly Heating & Air Conditioning. We've long focused on enhancing indoor air quality in Iowa City. Here, we’ve answered frequent questions about HVAC filters, including that very tricky question of what direction do you point a filter in your furnace or air conditioner?
When Should I Replace My Furnace Air Filter?
Experts stress it's important 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 pull air through the plugged-up filter.
Officials advise inspecting your furnace filter every month and replacing it if it’s dirty. You’ll know if the filter needs to be changed because it will coated with dirt or dust. People who have pets that shed will very likely need 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 found in the return air duct or blower compartment before the return air goes back into the furnace. This ensures air flowing into the system is filtered before it goes 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, within the furnace. It's typically housed inside of a slot, frame or cabinet for convenient access and replacement. Always refer to your furnace's owner manual for important information regarding filter location of your 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 AC filter are basically the same. While people might refer to them differently based on the current season— summer or winter—they are all filters that clean the air in your home.
They each remove dust, allergens, bacteria and other particulates 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 Do I Need?
Once you locate your old furnace filter and determine when it should be substituted for a clean one, it’s time to select a replacement. That means picking the level of filtration that you need. One way to do that is by picking an appropriate MERV rating for your needs.
MERV is short 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 higher numbers indicating a greater ability to filter tinier particles.
Experts say a filter with a MERV rating between 8 and 13 offers an appropriate balance between having healthy indoor air quality without needlessly restricting airflow. However, people with specific health conditions could need a a higher MERV rating.
How to Place the Air Filter in a Furnace or Air Conditioner
Putting an air filter in a furnace or air conditioner properly is necessary for the efficient operation of the system. Air filters have a certain direction, indicated by an arrow printed on the side of the filter frame. The filter should be put in with this arrow pointing toward the furnace or AC, which is the direction of the airflow. If you're not sure about the airflow direction, try to remember that air always moves from the return duct towards the heat or cooling source. Therefore, make certain the arrow points in the direction of the furnace or air conditioner.
Many people struggle with which direction to face their system's air filter. To help remember, consider taking a quick picture with your cellular 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 point. A handy time to inquire about this is during a regular furnace maintenance call.
How to Change a Furnace Air Filter
Switching out the filter on your furnace or AC is a simple 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 shut off your furnace before beginning the process.
- Look for the furnace filter: Typically, the filter is positioned inside 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 clean filter to point in the same direction.
- Remove the old filter: Be diligent not to knock out any dust or particles.
- Record the date: Write down the date of replacement on the new filter's frame. This will help your family keep track of when it's time for you to change it again.
- Put 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 your last filter.
- Secure the filter: Make sure the new filter fits securely and close any latches or clips that secure it in place.
- Turn on your furnace: Once the new filter is completely in place, 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 reduce its lifespan. Changing your furnace or air conditioning filter is one of the simplest things you can do to keep your system working effectively.
