Picking out the proper 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 crucial role in keeping its system running safely, efficiently and for a long time.
A dirty furnace filter loses its effectiveness, allowing potentially harmful particles to circulate through your home. It also limits airflow, which can damage your furnace and reduce its life span.
Making sure your furnace uses a clean filter that is suitable for your needs is not merely about keeping your furnace running efficiently. It’s also about delivering excellent indoor air quality for your home.
Your health is important to the HVAC pros at Pliescott HVAC Services LLC. We've long been dedicated to enhancing indoor air quality in Cambridge. 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 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 more energy to force air through the plugged-up filter.
Officials advise inspecting your furnace filter every 30 days and replacing it if it’s dirty. You’ll know if it is dirty because it will coated with dirt or dust. Those who have pets that shed will probably want to replace their furnace air filter more often, because a good 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 goes back into the furnace. This ensures air flowing into 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 in a slot, frame or cabinet for easy access and replacement. Always refer to your furnace's owner manual for important 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 essentially the same. While they might be called different things based on the current season— summer or winter—they are all filters that clean the air in your HVAC system.
They each get rid of dust, allergens, bacteria and other particulates from the air that is drawn into the furnace and air conditioning system, ensuring 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 determine when it should be replaced, it’s time to select a replacement. That means determining the level of filtration that you need. One way to do that is by choosing an appropriate MERV rating for your needs.
MERV stands 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 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 could need to use a filter with a higher MERV rating.
Which Way to Put the Air Filter in a Furnace or Air Conditioner
Putting an air filter in a furnace or air conditioner correctly is crucial for the efficient operation of the unit. Air filters have a certain direction, indicated by an arrow printed 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 conditioning unit, which is the direction of the airflow. If you're unsure about the airflow direction, remember that air always moves from the return duct and then to the heat or cooling source. Therefore, be sure that the arrow points in the direction of the furnace or AC.
Many people are confused by which direction to face an 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 be installed. A perfect time to do this is during a routine furnace maintenance call.
How to Change a Furnace Air Filter
Changing the filter on your furnace or air conditioning system is a simple process. Here is a step-by-step rundown of how to retreive a dirty air filter and replace it with a new one:
- 1. Turn off your furnace: Make sure to switch off your furnace before beginning the process.
- Find the furnace filter: Typically, the filter is found within 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.
- Remove the old filter: Be mindful not to knock out any dust or debris.
- 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 the next change.
- Insert 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 dirty filter you just removed.
- Secure the filter: Make sure the new filter fits correctly and close any latches or clips that lock it in the compartment.
- Turn on your furnace: Once the replacement filter is properly secured, 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 cease working or decrease its lifespan. Changing your furnace or AC filter is one of the best things you can do to keep your system operating effectively.