Choosing the correct 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 role in keeping its system running safely, efficiently and for a long time.
A clogged furnace filter loses its effectiveness, permitting potentially harmful particles to move through your home. It also restricts airflow, which can damage your furnace and shorten its life span.
Making sure your furnace uses a clean filter that is ideal for your needs is not merely about keeping your furnace running efficiently. It’s also about creating healthy indoor air quality for your home.
Your health is important to the heating and cooling specialists at Stieferman Heating Company Inc. We've long been dedicated to improving indoor air quality in Jefferson City. 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?
How Often to Replace the Air Filter in a Furnace
It's vital to replace dirty air filters in a furnace or air conditioner regularly. Dirt-clogged filters cause the system to worker harder than it should because it takes extra work to force air through the plugged-up filter.
Officials advise checking 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. Those who have pets will likely need 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 found 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 goes 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 usually housed within a slot, frame or cabinet for convenient access and replacement. Always refer to your furnace's owner manual for information regarding 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 AC filter are effectively the same thing. 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 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 sure the air distributed throughout your home is clean and safe.
What Are MERV Ratings and What MERV Rating Should I Have?
Once you track down your old furnace filter and determine when it should be replaced, it’s time to choose a replacement. That means picking the level of filtration that you need. One method to do this is by choosing an appropriate MERV rating for your needs.
MERV stands for Minimum Efficiency Reporting Values. The MERV rating indicates the effectiveness of air filters at trapping airborne contaminants. The rating scale ranges from 1 to 20, with greater numbers indicating enhanced capabilities to filter smaller particles.
Experts say a filter with a MERV rating between 8 and 13 offers an appropriate 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 Conditioning System
Installing an air filter in a furnace or air conditioner the proper way is necessary for the efficient operation of the system. Air filters are designed to be installed in a particular 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 in the direction of the furnace or air conditioner, 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 at the furnace or AC.
Many people struggle with which direction to install their system's air filter. To help remember, consider taking a quick picture with your cell 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 great time to do this is during a regular furnace maintenance call.
Changing Your Furnace's Air Filter
Replacing the filter on your furnace or air conditioning system is a simple process. Here is a step-by-step breakdown of how to take out a dirty air filter and exchange it for a new one:
- Turn off your furnace: Make a point to switch off your furnace before starting up the process.
- Locate the furnace filter: Typically, the filter is located 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 new filter to point in the same direction.
- Slide 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 make it easier to keep track of when it's time for another replacement.
- Slide in 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 your last filter.
- Secure the filter: Make sure the new filter fits securely and close any latches or clips that secure it in place.
- Turn on your furnace: Once the clean filter is completely secured, you can turn your furnace back on.
Will a Dirty Air Filter Damage My Furnace?
The shortest answer is, yes, a dirty air filter can cause a furnace to stop working or shorten its lifespan. Changing your furnace or AC filter is one of the simplest things you can do to keep your system working efficiently.