Picking out the correct furnace filter and changing it when it becomes 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 running safely, efficiently and for a long time.
A dirty furnace filter loses its effectiveness, enabling potentially harmful particles to move 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 suitable for your needs is not only about keeping your furnace operating efficiently. It’s also about providing good indoor air quality for your residence.
Your health is important to the heating specialists at Ilten's. We've long focused on enhancing indoor air quality in Cedar Rapids. 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 Should I Replace My Furnace Air Filter?
It is critical to replace dirty air filters in a furnace or air conditioner periodically. Dirty filters cause the system to worker harder than it should because it takes extra effort to force air through the plugged-up filter.
Officials advise examining your furnace filter monthly and replacing it if it’s dirty. You’ll know if your filter needs changing because it will filled with dirt or dust. Homeowners 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.
How to Find the Furnace's Air Filter
In general, a furnace air filter is usually found in the return air duct or blower compartment before the return air gets to the furnace. This ensures air flowing into the system is filtered before it moves through the furnace components and is heated.
Depending on the furnace model, 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 convenient access and replacement. Always refer to your furnace's owner manual for details regarding filter location of your furnace.
Is a Furnace Filter the Same as an Air Filter?
The simple answer is, yes. In HVAC, a furnace filter and an air filter or air conditioning filter are effectively the same. While people may call them different things based on the current season— warm or chilly months—they are all filters that clean the air in your residence.
They each remove dust, allergens, bacteria and other airborne debris 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 Is the MERV Rating System 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 choose 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 short for Minimum Efficiency Reporting Values. The MERV rating measures the effectiveness of air filters at trapping airborne contaminants. The rating scale ranges from 1 to 20, with higher numbers indicating enhanced capabilities to filter tinier particles.
Experts say a filter with a MERV rating between 8 and 13 offers an ideal balance between having adequate indoor air quality without unnecessarily restricting airflow. However, people with specific health conditions could need to purchase a filters with a higher MERV rating.
Which Way to Put the Air Filter in a Furnace or AC Unit
Positioning an air filter in a furnace or air conditioner correctly is important for the efficient operation of the unit. Air filters are designed to be installed in a certain direction, indicated by an arrow located on the side of the filter frame. The filter should be placed in the unit with this arrow pointing at the furnace or air conditioning unit, which is the direction of the airflow. If you're unsure about the airflow direction, try to remember that air always moves from the return duct and then to the heat or cooling source. Therefore, be sure that the arrow points at the furnace or AC.
Many people struggle with which direction to install their 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 scheduled furnace maintenance call.
How to Change a Furnace Air Filter
Replacing the filter on your furnace or air conditioning system is an easy process. Here is a step-by-step list of how to remove a dirty air filter and replace it with a new one:
- Turn off your furnace: Make sure to shut off your furnace before starting the process.
- Look for 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 replacement filter to point the same way.
- Take out the old filter: Be careful not to knock out any dust or dirt.
- Note the date: Write down the date you replaced the filter 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 toward 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 new filter is safely installed, you can turn your furnace back on.
Can a Dirty Air Filter Cause Problems for a Furnace?
The short answer is, yes, a dirty air filter can cause a furnace to stop working or shorten its lifespan. Changing your furnace or air conditioner filter is one of the easiest things you can do to keep your system running effectively.