Picking out the right 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 crucial role 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 shorten its life span.
Ensuring your furnace uses a clean filter that is appropriate for your needs is not merely about keeping your furnace running efficiently. It’s also about providing healthy indoor air quality for your household.
The quality of the air your family breathes is important to the HVAC pros at Olde Towne Heating & Air. We've long worked with an eye on improving indoor air quality in Mount Pleasant. 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 critical 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 recommend examining 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. Those who have pets that shed will probably need 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 normally installed in the return air duct or blower compartment before the return air gets to the furnace. This ensures air entering the system is filtered before it goes through the furnace components and is heated.
Depending on the furnace brand, the filter may be located 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 regarding 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 basically identical. While people may call them different things based on the current season— hot or cold—they are all filters that clean the air in your HVAC system.
They each remove dust, allergens, bacteria and other particulates from the air that is drawn into the furnace and air conditioning system, making sure the air circulating throughout 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 determine when it should be replaced, it’s time to select 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 is short for Minimum Efficiency Reporting Values. The MERV rating measures the effectiveness of air filters at trapping airborne molecules. The rating scale ranges from 1 to 20, with greater numbers indicating enhanced capabilities 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 unnecessarily restricting airflow. However, people with certain health conditions may 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 properly 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 toward 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 at the furnace or AC.
Many people struggle with which direction to face 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 be installed. A great time to inquire about this is during a regular furnace maintenance call.
How to Change a Furnace Air Filter
Changing the filter on your furnace or air conditioner is a quick and easy process. Here is a step-by-step breakdown of how to take out a dirty air filter and exchange it for a new one:
- 1. Turn off your furnace: Make sure to turn off your furnace before starting up the process.
- Find the furnace filter: Typically, the filter is located inside 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 clean filter to point similarly.
- Slide out the old filter: Be mindful 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 you to change it again.
- Put in new filter: Put in the new filter with the arrow pointing in the direction of 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 hold it in the unit.
- Turn on your furnace: Once the new filter is properly installed, you can turn your furnace back on.
Will a Dirty Air Filter Cause a Furnace Not to Work?
The short answer is, yes, a dirty air filter can cause a furnace to quit working or reduce its lifespan. Changing your furnace or AC filter is one of the simplest things you can do to keep your system working effectively.