Choosing 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 critical function in keeping its system operating safely, efficiently and for a long time.
An overused furnace filter loses its effectiveness, allowing potentially harmful particles to move through your home. It also restricts airflow, which can damage your furnace and decrease its life span.
Making certain your furnace uses a clean filter that is suitable for your needs is not just about keeping your furnace running efficiently. It’s also about providing good indoor air quality for your household.
The health of your family is important to the heating pros at Kohles & Bach Heating & Cooling. We've long worked with an eye on improving indoor air quality in Des Moines. 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 to Replace the Air Filter in Your Furnace
It's critical to replace dirty air filters in a furnace or air conditioner routinely. 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 checking your furnace filter every 30 days 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 dogs and cats will very likely have to replace their furnace air filter more often, because an effective air filter will trap pet hair circulating in a home.
Locating Your 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 gets to the furnace. This is so air flowing into the system is filtered before it moves through the furnace components and is heated.
Depending on the furnace brand, the filter may be found on the right, left, bottom or in some cases, inside 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 information about filter location of your furnace.
Are Air Filters and Furnace Filters the Same Thing?
The easy answer is, yes. In HVAC, a furnace filter and an air filter or AC filter are effectively identical. 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 HVAC system.
They each eliminate 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 Are MERV Ratings and What Rating Is Best for Me?
Once you locate your old furnace filter and decide when it should be substituted for a clean one, it’s time to choose a replacement. That means determining the level of filtration that you need. One method to do this is by picking an appropriate MERV rating for your needs.
MERV is an abbreviation 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 greater numbers indicating a greater ability to filter small particles.
Experts say a filter with a MERV rating between 8 and 13 offers an appropriate balance between having good indoor air quality without needlessly restricting airflow. However, people with certain health conditions might need a a higher MERV rating.
Which Way to Put the Air Filter in a Furnace or AC Unit
Installing an air filter in a furnace or air conditioner correctly is crucial for the efficient operation of the unit. Air filters have a specific direction, indicated by an arrow located on the side of the filter frame. The filter should be installed with this arrow pointing in the direction of the furnace or air conditioning unit, 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 and then to the heat or cooling source. Therefore, make sure the arrow points toward the furnace or air conditioner.
Many people are confused by which direction to install their air filter. To help remember, consider taking a picture with your cell 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 perfect time to ask about this is during a routine furnace maintenance visit.
How to Replace Your Furnace Air Filter
Replacing the filter on your furnace or AC is an easy process. Here is a step-by-step rundown of how to remove a dirty air filter and swap it for a new one:
- Turn off your furnace: Make sure to switch off your furnace before beginning the process.
- Locate the furnace filter: Typically, the filter is found inside the furnace or in the air return vent. Take 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.
- 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 old filter you are replacing.
- Secure the filter: Make sure the new filter fits correctly and close any latches or clips that lock it in the unit.
- Turn on your furnace: Once the new filter is completely in place, you can turn your furnace back on.
Can a Dirty Air Filter Damage My Furnace?
The simple answer is, yes, a dirty air filter can cause a furnace to stop working or reduce its lifespan. Changing your furnace or AC filter is one of the easiest things you can do to keep your system operating effectively.