Replacing your furnace filter is vital for good air quality and efficient HVAC operation. A dirty, clogged filter strains the system, leading to long-term damage and higher utility bills. The good news is that furnace filter replacement is straightforward—you can do it yourself without calling in a professional HVAC engineer.
This article provides a step-by-step guide to changing furnace filters, including a video to show you how. We also examine some common mistakes people make when changing their furnace filters. Most importantly, we'll explain how to buy the right filter for your furnace or HVAC system.
Watch Our Step-by-Step Guide to Installing a New Furnace Filter
Furnace Filters are also know as air filters, HVAC filters, AC Filters, or Air Conditioner Filters. A dirty air filter can put a strain on your HVAC system causing long term damage to the equipment and increase your utility bills. You can then close the grill, close the latches and restart your system by pressing the mode button on your control until it is in the designed operation mode. In this case the system was put in to AUTO mode.
Turn Off Your AC or Heat by Changing the Mode to OFF
When replacing a filter behind a return grill vent, simply turn off your HVAC by turning off the unit from the control on the wall. This will turn off the motor and take the suction out of the system making it easy to remove the filter. Just press the mode button until it indicate off on the display. For some thermostats, you may just have an off switch.
Notice in the image Auto is selected. By pressing the mode button the selection will move to the next operation. In the image above you would press mode once to move the selection to off.
How to Locate Your Furnace Filters
If you have asked where are my air filters located in my home? You are not alone. Your air filter can be located in the blower compartment of your furnace, in an attached filter case or cabinet, or in a wall-mounted return air grille.
Air Filter Located Behind Return Grills
AC Filters are often located on the wall behind a return grill. If your filters are located in the return grill you may have multiple air filters to replace. Locate all of the return grills in the house. You may also have different size filters in each return. Don't assume they are all the same size. Check before ordering your filters.
Sometimes you can see the filter behind the return grill. If the return grill has filters, it probably has a latch instead of screws. The latch can be on the top, side or bottom of the grill depending on how it was installed. The image below has a 2 latches on the bottom that swing out to unlock and open the grill.
Pull down on latches to open the grill and replace the AC filter. be careful when removing the grill that the whole grill doses not fall. It is a good idea to hold the grill securely when opening.
Find Your 1 inch Air Filters by Size
Once both latches are open the grill can open and the dirty filter can be replaced with a new air filter.
Reset the Filter
Most thermostat controls have a setting to reset the filter. This will create an alert or reminder on the control, usually at a set period such as, 3 months, when it is time to change your filter.
On this control the filter reset is on the bottom left in the red box. Pressing the filter button resets the filter alarm so you will receive a warning on the display when it is time to change the filter. Setting a filter subscription is another good way to make sure you change your filters when it is time to properly maintain your system.
Expert Tip: Put FAN ON LOW to Maintain AIR QUALITY
There are a few benefits of continuously running the fan on an HVAC system, including:
- Improved Indoor Air Quality: Running the fan continuously can help to circulate air and remove impurities, such as pollen, dust, and pet dander, resulting in improved indoor air quality.
- Increased Comfort: Running the fan continuously can help to distribute cool or warm air throughout the home, resulting in more consistent temperatures and increased comfort.
- Enhanced Energy Efficiency: Running the fan continuously can help to reduce the load on the HVAC system, potentially reducing the amount of energy required to heat or cool the home.
- Improved Humidity Control: Running the fan continuously can help to control humidity levels in the home, preventing mold and mildew growth, and promoting overall comfort.
Evenly Distribute Air Through Out the Home
When the fan is running it does not take the home as long to heat up or cool down as when the fan is not running. When a fan is running, it helps to distribute the air generated by the HVAC system more evenly throughout the space, which can allow the temperature to reach the desired level more quickly. This means that the HVAC system doesn't have to run as long to achieve the desired temperature, which can help to reduce the amount of energy consumed.
By circulating the air, the fan can also help to reduce hot and cold spots in the home, which can make the environment more comfortable. This can be especially beneficial in homes with poorly insulated rooms or high ceilings, where it can be difficult to maintain a consistent temperature.
Energy Consumption
It's important to note that running a fan continuously can also consume energy, so it's not just about the reduction of energy consumption by the HVAC system. However, in many cases, the energy saved by the HVAC system can outweigh the energy consumed by the fan, leading to overall increased energy efficiency.
** It's important to note that the benefits of continuously running the fan can vary depending on the HVAC system and the home's specific needs. Before making the decision to run the fan continuously, it is recommended to consult with a professional to determine the best course of action for your specific HVAC system and home.
Furnace Filters located in a Cabinet or Case
Many furnaces have a compartment or a cabinet for a whole house air filter such as this Lennox furnace filter in it own cabinet.
Now that you have located your filter.
Buy Your Replacement Filter Now
Find Your Filter Easily
Enter The Filter Part Number or Size from Your Current Filter in the Search, for example, enter X8795 or 20x20x1.
Avoiding Common Mistakes When Changing a Furnace Filter
Here are some of the most common mistakes people make when changing their furnace or HVAC air filter and how to avoid them.
Installing the Filter Backwards
One of the most frequent errors is installing the air filter backward. Air filters are manufactured to allow airflow in only one direction. There is usually an arrow on the filter frame indicating the proper airflow direction—make sure this arrow points toward the furnace and away from the return duct. Installing the filter backward restricts airflow and makes your HVAC system work harder.
Forgetting to Change the Furnace Filter Regularly
Many people forget or neglect to change furnace filters often enough. Dirty, clogged filters restrict airflow, reduce efficiency, and can even damage HVAC systems. Depending on the type and household conditions, filters should generally be changed every 1-3 months.
Choosing the Wrong Filter Size
Another common mistake is buying a filter that is the incorrect size for your HVAC system. An undersized filter allows unfiltered air to flow around the edges, while one that is too large won't fit. Check the dimensions printed on the side of your current filter when buying a replacement.
Selecting a Filter with the Wrong Efficiency Rating
HVAC filters have efficiency ratings, usually MERV ratings, that indicate how well they remove particles from the air. A filter with a MERV rating that is too high can restrict airflow too much and damage your system. A MERV rating that is too low will not properly clean your air.
We recommendMERV 13 filters for optimal filtration, but you should check your HVAC manual to ensure they are compatible with your system. We also supplyMERV 8 andMERV 11 furnace filters.
Not Turning Off the HVAC System Before Changing the Filter
For safety, it's important to always turn off your HVAC system at the thermostat or breaker before opening the filter compartment to change the filter. Failing to do so can allow unfiltered air into the system while it's running.
How to Buy the Right Replacement Filter for Your Furnace
Determine the Correct Filter Size
The most important factor is getting the right size filter. There are a few ways to do this:
- Check the size printed on the side of your existing filter. It is usually the nominal size, rounded to the nearest whole inch, such as 20x25x1.
- If the size is not printed, measure the existing filter's length, width, and depth. Round each measurement up to the nearest whole inch to get the nominal size.
- If you don't have an existing filter, measure the filter slot or frame in your furnace. The filters’ actual size will be about 0.25-0.5 inches smaller than the slot dimensions.
Once you know the filter size, use the furnace filter search box on this page to identify the best replacement furnace filter for your system. Alternatively, visit ourair filter size chart to determine the correct replacement filter by brand, nominal size, actual size, and desired MERV rating.
Choose the Right MERV Rating
MERV stands for Minimum Efficiency Reporting Value and rates a filter's ability to capture particles. For residential use, MERV 8-13 is usually sufficient. Higher MERV ratings provide better filtration but can restrict airflow if your furnace is not designed for it, so ensure the filter you select is compatible with your system.
Learn more about the difference betweenMERV 8 and MERV 11 filters andMERV 11 and MERV 13 filters.
Select a Filter Type
Pleated filters are generally more effective than non-pleated fiberglass filters because they have a larger surface area, so they can trap more particles. They are excellent at trapping dust, pollen, mold spores, and other allergens, making them ideal for households with allergy sufferers. Also, pleated filters have a longer lifespan than fiberglass filters, meaning they don’t need to be replaced as frequently.
The key is to get the right combination of size, MERV rating, and filter type that provides good filtration and airflow for your specific furnace. When in doubt, check your manual, measure carefully, and don't hesitate to ask an HVAC professional for advice.
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