Picking out the right 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 crucial role in keeping its system running safely, efficiently and for a long time.
An overused furnace filter loses its effectiveness, permitting potentially harmful particles to circulate through your home. It also slows airflow, which can damage your furnace and shorten its life span.
Ensuring your furnace uses a clean filter that is ideal for your needs is not just about keeping your furnace running efficiently. It’s also about delivering healthy indoor air quality for your household.
Your health is important to the heating and cooling professionals at Retro HVAC Service & Installation. We've long been dedicated to improving indoor air quality in Philadelphia. 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?
When Should I Replace My Furnace Air Filter?
It is vital 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 more energy to move 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. People who have pets will very likely need to replace their furnace air filter more often, because an effective air filter will trap pet hair circulating in a home.
Locating Your Furnace's Air Filter
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 is so air entering the system is filtered before it moves through the furnace components and is heated.
Depending on the furnace model, the filter may be located on the right, left, bottom or in some cases, inside the furnace. It's generally housed inside of a slot, frame or cabinet for simple access and replacement. Always refer to your furnace's owner manual for information regarding filter location of your particular brand and model of 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 conditioning filter are effectively 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 remove dust, allergens, bacteria and other contaminants from the air that is drawn into the furnace and air conditioning system, ensuring 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 substituted for a clean one, it’s time to choose 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 measures the effectiveness of air filters at trapping airborne contaminants. The rating scale ranges from 1 to 20, with higher numbers indicating enhanced capabilities to filter small particles.
Experts say a filter with a MERV rating between 8 and 13 offers a good balance between having good indoor air quality without needlessly restricting airflow. However, people with specific health conditions may need a a higher MERV rating.
Where to Insert the Air Filter in a Furnace or AC Unit
Putting an air filter in a furnace or air conditioner correctly is necessary for the efficient operation of the unit. 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 in the direction of the furnace or AC, which is the direction of the airflow. If you're doubtful about the airflow direction, it may be helpful to remember that air always moves from the return duct and then to the heat or cooling source. Therefore, be sure that the arrow points toward the furnace or air conditioner.
Many people have difficulty remembering which direction to point an air filter. To help remember, consider taking a picture with your cellular 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 handy time to inquire about this is during a routine furnace maintenance appointment.
How to Replace Your Furnace Air Filter
Changing 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 replace it with a new one:
- Turn off your furnace: Be sure to turn off your furnace before beginning the process.
- Locate the furnace filter: Typically, the filter is positioned in 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 replacement filter to point in the same direction.
- Take out the old filter: Be mindful not to knock out any dust or particles.
- Record the date: Write down the date of replacement on the new filter's frame. This will help you keep track of when it's time for you to change it again.
- Slide in new filter: Put in the new filter with the arrow pointing toward the furnace, which is the direction of airflow and should be the same direction the arrow pointed on the old filter you are replacing.
- 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 replacement filter is completely installed, you can turn your furnace back on.
Can 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 shorten its lifespan. Changing your furnace or air conditioning filter is one of the simplest things you can do to keep your system operating efficiently.