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 part in keeping its system operating safely, efficiently and for a long time.
A dirty furnace filter loses its effectiveness, permitting 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 appropriate for your needs is not only about keeping your furnace operating efficiently. It’s also about providing healthy indoor air quality for your household.
Your health is important to the HVAC specialists at Bishop Heating & Air Conditioning. We've long focused on enhancing indoor air quality in Bishop. Here, we’ve answered frequent 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 is critical to replace dirty air filters in a furnace or air conditioner periodically. Soiled filters cause the system to worker harder than it should because it takes more energy to force air through the plugged-up filter.
Officials recommend inspecting your furnace filter every 30 days and replacing it if it’s dirty. You’ll know if it is dirty because it will filled with dirt or dust. Those who have pets that shed will likely want to replace their furnace air filter more often, because an effective 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 goes back into the furnace. This is so air flowing into the system is filtered before it goes through the furnace components and is heated.
Depending on the furnace model, the filter may be positioned on the right, left, bottom or in some cases, on the inside of 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 important information concerning 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 conditioner filter are essentially identical. 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 HVAC system.
They each remove dust, allergens, bacteria and other contaminants from the air that is drawn into the furnace and air conditioning system, making sure the air flowing through your home is clean and safe.
What Is a MERV Rating and What MERV Rating Do I Need?
Once you locate your old furnace filter and determine 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 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 bigger numbers indicating enhanced capabilities to filter small particles.
Experts say a filter with a MERV rating between 8 and 13 offers a good balance between having healthy indoor air quality without overly restricting airflow. However, people with certain health conditions could need a a higher MERV rating.
Which Way to Put the Air Filter in a Furnace or Air Conditioner
Putting an air filter in a furnace or air conditioner the proper way is crucial for the efficient operation of the heating or cooling system. Air filters are designed to be installed in 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 toward the furnace or air conditioning unit, 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 and then to the heat or cooling source. Therefore, make certain the arrow points in the direction of the furnace or air conditioner.
Many people are confused by which direction to install their air filter. To help remember, consider taking a quick picture with your cell 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 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 breakdown of how to remove a dirty air filter and exchange it for a new one:
- 1. Turn off your furnace: Make sure to shut off your furnace before starting up the process.
- Find 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.
- Remove the old filter: Be diligent not to knock out any dust or debris.
- Record the date: Write down the date you changed filters 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 the compartment.
- Turn on your furnace: Once the new filter is properly secured, 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 stop working or reduce its lifespan. Changing your furnace or air conditioner filter is one of the easiest things you can do to keep your system running correctly.