Picking out the right 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 part in keeping its system working 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 restricts airflow, which can damage your furnace and decrease its life span.
Making sure your furnace uses a clean filter that is ideal for your needs is not just about keeping your furnace working efficiently. It’s also about delivering excellent indoor air quality for your residence.
The quality of the air your family breathes is important to the heating specialists at Farnell Mechanical, Inc.. We've long been dedicated to improving indoor air quality in Auburn and Opelika. Here, we’ve answered frequent questions about HVAC filters, including that particularly tricky question of what direction do you point a filter in your furnace or air conditioner?
When to Replace the Air Filter in Your Furnace
Experts stress 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 move air through the plugged-up filter.
Officials recommend checking 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 be gray or black from dirt or dust. Those who have dogs and cats will very likely have to replace their furnace air filter more often, because a good air filter will trap pet hair circulating in a home.
Locating Your Furnace's Air Filter
In general, a furnace air filter is usually installed in the return air duct or blower compartment before the return air reaches the furnace. This ensures air flowing into the system is filtered before it passes 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, within the furnace. It's typically housed within a slot, frame or cabinet for easy access and replacement. Always refer to your furnace's owner manual for details about 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 conditioner filter are effectively the same thing. While people might refer to them differently based on the current season— hot or cold—they are all filters that clean the air in your residence.
They each get rid of 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 Are MERV Ratings and What Rating Is Best for Me?
Once you locate your old furnace filter and decide when it should be changed, it’s time to choose a replacement. That means deciding on the level of filtration that you need. One way to do that is by picking an appropriate MERV rating for your needs.
MERV is an abbreviation 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 higher numbers indicating a greater ability to filter tinier particles.
Experts say a filter with a MERV rating between 8 and 13 offers an ideal balance between having good indoor air quality without unnecessarily restricting airflow. However, people with certain health conditions may need to purchase a filters with a higher MERV rating.
How to Place the Air Filter in a Furnace or AC Unit
Positioning an air filter in a furnace or air conditioner properly is necessary for the efficient operation of the unit. Air filters are supposed to face a certain 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 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, make sure the arrow points toward the furnace or air conditioning unit.
Many people have difficulty remembering which direction to install an air filter. To help remember, consider taking a picture with your mobile 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 be installed. A perfect time to ask about this is during a scheduled furnace maintenance appointment.
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 remove a dirty air filter and swap it for a new one:
- Turn off your furnace: Make sure to shut off your furnace before beginning the process.
- Locate the furnace filter: Typically, the filter is positioned 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.
- Remove the old filter: Be diligent not to knock out any dust or particles.
- Document 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 another replacement.
- 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 the old filter you are replacing.
- Secure the filter: Make sure the new filter fits securely and close any latches or clips that lock it in the unit.
- Turn on your furnace: Once the replacement filter is completely in place, you can turn your furnace back on.
Will a Dirty Air Filter Cause a Furnace Not to Work?
The shortest answer is, yes, a dirty air filter can cause a furnace to stop working or limit its lifespan. Changing your furnace or air conditioner filter is one of the best things you can do to keep your system running effectively.