Picking out the proper 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 crucial function in keeping its system working safely, efficiently and for a long time.

An overused furnace filter loses its effectiveness, allowing potentially harmful particles to circulate through your home. It also restricts airflow, which can damage your furnace and shorten its life span.

Ensuring your furnace uses a clean filter that is ideal for your needs is not just about keeping your furnace operating efficiently. It’s also about creating excellent indoor air quality for your residence.

The health of your family is important to the heating and cooling professionals at Cooks Air Conditioning and Heating Specialists. We've long been dedicated to enhancing indoor air quality in Palm Coast. Here, we’ve answered common 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's vital 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 more energy to move air through the plugged-up filter.

Officials recommend examining your furnace filter every month and replacing it if it’s dirty. You’ll know if your filter needs changing because it will filled with dirt or dust. People who have pets will probably want to replace their furnace air filter more often, because a good air filter will trap pet hair circulating in a home.

Locating Your Furnace's Air Filter

In general, a furnace air filter is normally located in the return air duct or blower compartment before the return air gets to the furnace. This is so air being pulled 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, on the inside of the furnace. It's generally housed within a slot, frame or cabinet for easy access and replacement. Always refer to your furnace's owner manual for information concerning filter location of the furnace in your home.

Are Air Filters and Furnace Filters the Same Thing?

The straightforward answer is, yes. In HVAC, a furnace filter and an air filter or air conditioner filter are essentially identical. 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 airborne debris 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 Is a MERV Rating and What MERV Rating Do I Need?

Once you find 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 approach to this is by choosing 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 bigger 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 good indoor air quality without unnecessarily restricting airflow. However, people with specific health conditions could need to use a filter with a higher MERV rating.

How to Place the Air Filter in a Furnace or Air Conditioning System

Positioning an air filter in a furnace or air conditioner the proper way is crucial for the efficient operation of the system. Air filters have a particular direction, indicated by an arrow located on the side of the filter frame. The filter should be put in with this arrow pointing at the furnace or air conditioner, which is the direction of the airflow. If you're not sure about the airflow direction, it may be helpful to remember that air always moves from the return duct to the heat or cooling source. Therefore, make sure the arrow points in the direction of the furnace or AC.

Many people struggle with which direction to point an air filter. To help remember, consider taking a quick 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 go. A perfect time to inquire about this is during a routine furnace maintenance appointment.

Changing Your Furnace's Air Filter

Switching out the filter on your furnace or air conditioning system is an easy process. Here is a step-by-step rundown of how to take out a dirty air filter and swap it for a new one:

  1. Turn off your furnace: Make sure to turn off your furnace before beginning the process.
  2. Find the furnace filter: Typically, the filter is positioned inside the furnace or in the air return vent. Make a mental note or write down which direction the arrow points on the filter, because you’ll want the arrow on the new filter to point in the same direction.
  3. Remove the old filter: Be careful not to knock out any dust or dirt.
  4. Note the date: Write down the date you replaced the filter on the new filter's frame. This will make it easier to keep track of when it's time for another replacement.
  5. Insert new filter: Put in the new filter with the arrow pointing at the furnace, which is the direction of airflow and should be the same direction the arrow pointed on the old filter you are replacing.
  6. Secure the filter: Make sure the new filter fits securely and close any latches or clips that secure it in place.
  7. Turn on your furnace: Once the clean filter is completely secured, you can turn your furnace back on.

Will a Dirty Air Filter Cause Problems for a Furnace?

The simple 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 simplest things you can do to keep your system running efficiently.