Choosing the ideal 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 vital role in keeping its system operating safely, efficiently and for a long time.
A dirty furnace filter loses its effectiveness, permitting potentially harmful particles to move through your home. It also limits airflow, which can damage your furnace and shorten its life span.
Making certain your furnace uses a clean filter that is suitable for your needs is not merely about keeping your furnace working efficiently. It’s also about providing excellent indoor air quality for your home.
Your health is important to the HVAC specialists at Gilray Heating and Cooling. We've long worked with an eye on improving indoor air quality in Wausau. 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's 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 extra work to pull air through the plugged-up filter.
Officials recommend examining your furnace filter monthly and replacing it if it’s dirty. You’ll know if your filter needs changing because it will be gray or black from dirt or dust. Homeowners who have pets 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.
Where Is the Air Filter in My Furnace?
In general, a furnace air filter is normally found in the return air duct or blower compartment before the return air goes back into 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 found on the right, left, bottom or in some cases, inside the furnace. It's generally housed in a slot, frame or cabinet for simple access and replacement. Always refer to your furnace's owner manual for important information about filter location of your furnace.
Is a Furnace Filter the Same as an Air Filter?
The straightforward answer is, yes. In HVAC, a furnace filter and an air filter or air conditioner filter are basically the same thing. 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 home.
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 find your old furnace filter and figure out when it should be changed, it’s time to pick a replacement. That means deciding on the level of filtration that you need. One method to do this is by selecting 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 contaminants. The rating scale ranges from 1 to 20, with bigger numbers indicating the power to filter tinier particles.
Experts say a filter with a MERV rating between 8 and 13 offers an appropriate balance between having adequate indoor air quality without needlessly 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 important for the efficient operation of the unit. Air filters are supposed to face a specific direction, indicated by an arrow located 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 unsure about the airflow direction, try to remember that air always moves from the return duct towards the heat or cooling source. Therefore, be sure that the arrow points at the furnace or air conditioner.
Many people are confused by which direction to install their system's air filter. To help remember, consider snapping a quick photo with your cellular 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 handy time to ask about this is during a routine furnace maintenance visit.
How to Change a Furnace Air Filter
Switching out the filter on your furnace or AC is a quick and easy process. Here is a step-by-step list of how to retreive a dirty air filter and exchange it for a new one:
- 1. Turn off your furnace: Make a point to switch off your furnace before beginning the process.
- Locate the furnace filter: Typically, the filter is located 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 clean filter to point similarly.
- Slide out the old filter: Be careful not to knock out any dust or particles.
- Note the date: Write down the date you changed filters on the new filter's frame. This will help you keep track of when it's time for another replacement.
- Insert 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 the dirty filter you just removed.
- 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 new filter is completely installed, 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 quit 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 operating effectively.