Selecting the correct 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 function in keeping its system operating 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.
Making sure your furnace uses a clean filter that is appropriate for your needs is not just about keeping your furnace working efficiently. It’s also about creating excellent indoor air quality for your household.
Your health is important to the HVAC specialists at Stieferman Heating Company Inc. We've long worked with an eye on bettering indoor air quality in Jefferson City. 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'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 extra effort to force air through the plugged-up filter.
Officials suggest inspecting 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. Homeowners who have pets will likely need to replace their furnace air filter more often, because an effective 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 commonly found 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 brand, the filter may be located on the right, left, bottom or in some cases, within 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 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 essentially the same. 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 home.
They each get rid of dust, allergens, bacteria and other airborne debris from the air that is drawn into the furnace and air conditioning system, ensuring the air distributed throughout your home is clean and safe.
What Is the MERV Rating System 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 choose a replacement. That means picking the level of filtration that you need. One approach to this is by choosing an appropriate MERV rating for your needs.
MERV is short 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 greater numbers indicating a greater ability to filter tinier particles.
Experts say a filter with a MERV rating between 8 and 13 offers a good balance between having healthy indoor air quality without needlessly restricting airflow. However, people with specific health conditions may need to use a filter with a higher MERV rating.
Which Way to Put the Air Filter in a Furnace or AC Unit
Installing an air filter in a furnace or air conditioner the proper way is necessary for the efficient operation of the unit. Air filters are supposed to face a particular direction, indicated by an arrow printed on the side of the filter frame. The filter should be installed with this arrow pointing at the furnace or air conditioning unit, which is the direction of the airflow. If you're not sure 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, make sure the arrow points in the direction of the furnace or AC.
Many people have difficulty remembering which direction to face their system's air filter. To help remember, consider taking a quick 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 handy time to ask about this is during a regular furnace maintenance appointment.
How to Replace Your Furnace Air Filter
Changing the filter on your furnace or air conditioning system is a quick and easy process. Here is a step-by-step list of how to take out a dirty air filter and replace it with a new one:
- Turn off your furnace: Make sure to turn off your furnace before beginning the process.
- Find the furnace filter: Typically, the filter is found inside the furnace or in the air return vent. Make a mental note or write down which direction the arrow points on the filter, because you’ll want the arrow on the replacement filter to point the same way.
- Take out the old filter: Be diligent not to knock out any dust or dirt.
- Document the date: Write down the date you replaced the filter on the new filter's frame. This will help you keep track of when it's time for the next change.
- Slide in 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 the old filter you are replacing.
- Secure the filter: Make sure the new filter fits nicely and close any latches or clips that hold it in the unit.
- Turn on your furnace: Once the replacement filter is safely in place, you can turn your furnace back on.
Will a Dirty Air Filter Cause Problems for a Furnace?
The shortest answer is, yes, a dirty air filter can cause a furnace to quit working or shorten its lifespan. Changing your furnace or air conditioner filter is one of the best things you can do to keep your system operating correctly.