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 crucial part in keeping its system operating safely, efficiently and for a long time.
A dirty furnace filter loses its effectiveness, enabling potentially harmful particles to circulate through your home. It also limits airflow, which can damage your furnace and shorten its life span.
Making certain 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 creating good indoor air quality for your residence.
Your health is important to the heating pros at Fire & Ice HVAC. We've long focused on improving indoor air quality in Manassas. Here, we’ve answered common 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?
Experts stress it's vital to replace dirty air filters in a furnace or air conditioner routinely. Dirt-clogged filters cause the system to worker harder than it should because it takes extra effort to move 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 your filter needs changing because it will be gray or black from dirt or dust. Homeowners who have dogs and cats will likely have 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 commonly installed in the return air duct or blower compartment before the return air gets to the furnace. This is so air being pulled into the system is filtered before it passes through the furnace components and is heated.
Depending on the type of furnace, the filter may be positioned 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 facts concerning filter location of your particular brand and model of furnace.
Are Air Filters and Furnace Filters the Same Thing?
The simple answer is, yes. In HVAC, a furnace filter and an air filter or air conditioner filter are essentially identical. While they might be called different things based on the current season— warm or chilly months—they are all filters that clean the air in your residence.
They each remove dust, allergens, bacteria and other contaminants from the air that is drawn into the furnace and air conditioning system, making certain the air flowing through your home is clean and safe.
What Is the MERV Rating System and What Rating Is Best for Me?
Once you find your old furnace filter and decide when it should be changed, it’s time to select a replacement. That means deciding on the level of filtration that you need. One way to do that is by selecting an appropriate MERV rating for your needs.
MERV is short for Minimum Efficiency Reporting Values. The MERV rating calculates the effectiveness of air filters at trapping airborne molecules. The rating scale ranges from 1 to 20, with higher numbers indicating enhanced capabilities to filter smaller 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 some health conditions could 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 properly is necessary for the efficient operation of the system. Air filters have a specific direction, indicated by an arrow written 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 unsure about the airflow direction, 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 are confused by which direction to point an air filter. To help remember, consider snapping a quick photo 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 be installed. A great time to ask about this is during a regular furnace maintenance call.
How to Replace Your Furnace Air Filter
Replacing the filter on your furnace or AC is a quick and easy process. Here is a step-by-step list of how to remove a dirty air filter and exchange it for a new one:
- Turn off your furnace: Make sure to shut off your furnace before beginning the process.
- Look for the furnace filter: Typically, the filter is positioned 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 in the same direction.
- Take out the old filter: Be careful not to knock out any dust or particles.
- Note the date: Write down the date of replacement on the new filter's frame. This will help your family keep track of when it's time for the next change.
- Slide 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 correctly and close any latches or clips that hold it in the unit.
- Turn on your furnace: Once the clean filter is completely installed, you can turn your furnace back on.
Can a Dirty Air Filter Cause a Furnace Not to Work?
The short answer is, yes, a dirty air filter can cause a furnace to stop working or limit its lifespan. Changing your furnace or AC filter is one of the simplest things you can do to keep your system working effectively.