Picking out 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 dirty furnace filter loses its effectiveness, enabling potentially harmful particles to flow through your home. It also limits airflow, which can damage your furnace and decrease 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 healthy indoor air quality for your residence.
The health of your family is important to the HVAC specialists at B & G HVAC. We've long focused on improving indoor air quality in Marshalltown. 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?
How Often to Replace the Air Filter in a Furnace
Experts stress it's critical 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 force air through the plugged-up filter.
Officials recommend checking your furnace filter every month and replacing it if it’s dirty. You’ll know if the filter needs to be changed because it will coated with dirt or dust. Those who have pets will probably have 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 reaches the furnace. This is so 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 facts about filter location of the furnace in your home.
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 air conditioner filter are essentially the same thing. While people may call them different things based on the current season— summer or winter—they are all filters that clean the air in your home.
They each remove dust, allergens, bacteria and other airborne debris from the air that is drawn into the furnace and air conditioning system, making certain the air distributed throughout 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 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 picking an appropriate MERV rating for your needs.
MERV stands for Minimum Efficiency Reporting Values. The MERV rating indicates the effectiveness of air filters at trapping airborne particles. The rating scale ranges from 1 to 20, with higher numbers indicating a greater ability to filter small particles.
Experts say a filter with a MERV rating between 8 and 13 offers an ideal balance between having healthy indoor air quality without unnecessarily restricting airflow. However, people with certain health conditions might need a 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 necessary for the efficient operation of the system. Air filters have a particular direction, indicated by an arrow printed on the side of the filter frame. The filter should be put in 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, try to remember that air always moves from the return duct to the heat or cooling source. Therefore, be sure that the arrow points toward the furnace or air conditioning unit.
Many people struggle with which direction to face their air filter. To help remember, consider taking a quick picture with your mobile phone after the filter has been properly 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 ask about this is during a scheduled furnace maintenance appointment.
How to Change a Furnace Air Filter
Replacing the filter on your furnace or AC is an easy process. Here is a step-by-step rundown of how to remove a dirty air filter and exchange it for a new one:
- 1. Turn off your furnace: Be sure to shut off your furnace before starting up the process.
- Look for the furnace filter: Typically, the filter is located 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 similarly.
- Slide out the old filter: Be diligent not to knock out any dust or dirt.
- Document 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 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 old filter you are replacing.
- 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 completely in place, you can turn your furnace back on.
Will a Dirty Air Filter Cause a Furnace Not to Work?
The short answer is, yes, a dirty air filter can cause a furnace to cease working or decrease its lifespan. Changing your furnace or air conditioning filter is one of the easiest things you can do to keep your system operating correctly.