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 vital part in keeping its system running safely, efficiently and for a long time.
A clogged furnace filter loses its effectiveness, permitting potentially harmful particles to flow through your home. It also slows airflow, which can damage your furnace and reduce its life span.
Ensuring 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 healthy indoor air quality for your household.
Your health is important to the heating and cooling specialists at Air Current AC & Heat. We've long focused on improving indoor air quality in Houston. Here, we’ve answered frequent questions about HVAC filters, including that especially 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. Dirty filters cause the system to worker harder than it should because it takes extra effort to move air through the plugged-up filter.
Officials recommend inspecting your furnace filter every 30 days and replacing it if it’s dirty. You’ll know if your filter needs changing because it will filled with dirt or dust. Homeowners who have dogs and cats will very likely want to replace their furnace air filter more often, because a quality 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 usually located in the return air duct or blower compartment before the return air gets to the furnace. This makes sure air entering the system is filtered before it goes 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 in a slot, frame or cabinet for easy access and replacement. Always refer to your furnace's owner manual for important information about 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 AC filter are basically 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 residence.
They each eliminate dust, allergens, bacteria and other airborne debris from the air that is drawn into the furnace and air conditioning system, making sure the air flowing through your home is clean and safe.
What Is a MERV Rating and What MERV Rating Do I Need?
Once you locate your old furnace filter and decide when it should be substituted for a clean one, it’s time to pick a replacement. That means determining the level of filtration that you need. One method to do this is by choosing an appropriate MERV rating for your needs.
MERV is an abbreviation 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 greater numbers indicating the power 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 needlessly restricting airflow. However, people with specific health conditions might need to use a filter with a higher MERV rating.
Which Way to Put the Air Filter in a Furnace or Air Conditioner
Installing 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 have a particular direction, indicated by an arrow located on the side of the filter frame. The filter should be installed with this arrow pointing at the furnace or AC, which is the direction of the airflow. If you're unsure about the airflow direction, it may be helpful 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 conditioning unit.
Many people are confused by which direction to point an air filter. To help remember, consider taking a 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 go. A great time to inquire about this is during a regular furnace maintenance visit.
How to Change a Furnace Air Filter
Switching out the filter on your furnace or AC is a simple 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 sure to shut off your furnace before beginning the process.
- Find the furnace filter: Typically, the filter is positioned inside 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 new filter to point in the same direction.
- Slide out the old filter: Be diligent not to knock out any dust or dirt.
- Record the date: Write down the date you changed filters 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.
- 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 your last filter.
- Secure the filter: Make sure the new filter fits correctly and close any latches or clips that secure it in the unit.
- Turn on your furnace: Once the replacement filter is properly in place, 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 shorten its lifespan. Changing your furnace or AC filter is one of the easiest things you can do to keep your system running correctly.