Choosing 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 critical role in keeping its system working safely, efficiently and for a long time.
An overused furnace filter loses its effectiveness, allowing potentially harmful particles to flow through your home. It also limits airflow, which can damage your furnace and reduce its life span.
Ensuring your furnace uses a clean filter that is appropriate for your needs is not only about keeping your furnace running efficiently. It’s also about providing excellent indoor air quality for your home.
The health of your family is important to the HVAC professionals at Watts Electric & AC. We've long focused on improving indoor air quality in Columbia. Here, we’ve answered common 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 vital to replace dirty air filters in a furnace or air conditioner regularly. 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 advise examining your furnace filter every 30 days and replacing it if it’s dirty. You’ll know if your filter needs changing because it will coated with dirt or dust. People who have dogs and cats will very likely need 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 usually located in the return air duct or blower compartment before the return air goes back into the furnace. This ensures air being pulled into the system is filtered before it goes through the furnace components and is heated.
Depending on the type of furnace, the filter may be located on the right, left, bottom or in some cases, on the inside of the furnace. It's generally housed inside of 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.
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 conditioning 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 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 circulating throughout your home is clean and safe.
What Is a MERV Rating and What MERV Rating Should I Have?
Once you track down your old furnace filter and decide when it should be changed, it’s time to pick a replacement. That means determining 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 contaminants. The rating scale ranges from 1 to 20, with bigger numbers indicating a greater ability to filter small particles.
Experts say a filter with a MERV rating between 8 and 13 offers an appropriate balance between having adequate indoor air quality without unnecessarily restricting airflow. However, people with some health conditions could need to purchase a filters with a higher MERV rating.
How to Place the Air Filter in a Furnace or AC Unit
Putting an air filter in a furnace or air conditioner properly is crucial for the efficient operation of the unit. Air filters are supposed to face a certain direction, indicated by an arrow printed on the side of the filter frame. The filter should be installed with this arrow pointing toward the furnace or air conditioner, which is the direction of the airflow. If you're unsure about the airflow direction, try to remember that air always moves from the return duct and then to 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 their air filter. To help remember, consider taking a quick 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 inquire about this is during a scheduled furnace maintenance call.
Changing Your Furnace's Air Filter
Changing the filter on your furnace or AC is an easy process. Here is a step-by-step list of how to take out a dirty air filter and swap it for a new one:
- Turn off your furnace: Make a point to switch off your furnace before starting the process.
- Look for the furnace filter: Typically, the filter is found inside the furnace or in the air return vent. Take note of which direction the arrow points on the filter, because you’ll want the arrow on the replacement filter to point in the same direction.
- Slide out the old filter: Be diligent not to knock out any dust or debris.
- Document 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 another replacement.
- Insert 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 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 safely secured, 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 stop working or limit its lifespan. Changing your furnace or AC filter is one of the best things you can do to keep your system operating correctly.