Selecting the ideal 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 crucial function in keeping its system running safely, efficiently and for a long time.

A clogged furnace filter loses its effectiveness, enabling potentially harmful particles to circulate 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 appropriate for your needs is not merely about keeping your furnace working efficiently. It’s also about creating good indoor air quality for your home.

Your health is important to the heating specialists at Premium Air Services LLC. We've long been dedicated to improving indoor air quality in Tomball. 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?

How Often to Replace the Air Filter in a Furnace

It is 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 more energy to force 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 the filter needs to be changed because it will coated with dirt or dust. Those who have pets that shed will likely want to replace their furnace air filter more often, because a good 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 normally located in the return air duct or blower compartment before the return air reaches the furnace. This is so air being pulled into the system is filtered before it passes 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, inside the furnace. It's usually housed within 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 particular brand and model of 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 air conditioner filter are essentially the same. While they might be called different things based on the current season— hot or cold—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 distributed throughout your home is clean and safe.

What Is a MERV Rating and What MERV Rating Do I Need?

Once you track down your old furnace filter and determine when it should be substituted for a clean one, it’s time to choose 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 stands for Minimum Efficiency Reporting Values. The MERV rating calculates the effectiveness of air filters at trapping airborne molecules. The rating scale ranges from 1 to 20, with higher numbers indicating a greater ability to filter smaller particles.

Experts say a filter with a MERV rating between 8 and 13 offers a good balance between having adequate indoor air quality without unnecessarily restricting airflow. However, people with specific health conditions might need a a higher MERV rating.

Which Way to Put the Air Filter in a Furnace or Air Conditioner

Positioning 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 supposed to face a specific 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, remember that air always moves from the return duct and then to the heat or cooling source. Therefore, make certain the arrow points toward the furnace or air conditioner.

Many people struggle with which direction to install their system's air filter. To help remember, consider taking a quick picture with your mobile phone after the filter has been accurately 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 inquire about this is during a regular furnace maintenance visit.

How to Change a Furnace Air Filter

Replacing the filter on your furnace or air conditioner is a simple process. Here is a step-by-step rundown of how to take out a dirty air filter and exchange it for a new one:

  1. 1. Turn off your furnace: Make sure to shut off your furnace before starting up the process.
  2. Look for the furnace filter: Typically, the filter is found within 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 clean filter to point in the same direction.
  3. Remove the old filter: Be mindful not to knock out any dust or debris.
  4. Note the date: Write down the date of replacement 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 correctly and close any latches or clips that hold it in place.
  7. Turn on your furnace: Once the replacement filter is safely 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 limit its lifespan. Changing your furnace or air conditioning filter is one of the easiest things you can do to keep your system running correctly.