Simple Methods for Changing Your Furnace Filter (with Pictures)

1. 1

   Before checking or replacing the filter, turn off your furnace. Put the thermostat on the furnace in the "off" position. By doing this, the furnace won't start up while you're checking or changing the filter.

   • The furnace may suck up potentially harmful loose debris if it is turned on without a filter in place.
   • If your furnace's owner's manual provides any specific instructions on how to change the filter, consult it.

   Recommendation: Every month, check your filter to see if it needs to be replaced. The majority of disposable filters are meant to be changed every one to two months. Your filter will become dirty more quickly if you have furry pets or if your furnace runs constantly.

2. 2

   Slide the furnace's door panel off by opening it. Your furnace will have a door that either slides off or swings open. To provide access to the interior of your furnace, open or remove the door. [1]1

   • If your door slides off, you can usually remove it by simply lifting it until it does. Set it aside after removing the door.

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3. 3

   Find the furnace filter and remove any covers that are on it. The filter is typically situated at the air return duct or the blower chamber entrance. Sometimes you'll need to remove a different cover from the filter. [2]1

   • Locate the filter close to either the air return duct or the entrance to the blower chamber by looking for the vents where air enters the furnace system.

4. 4

   Hold the old filter up to the light after removing it. Carefully remove the filter for inspection by pulling it out with both hands. Hold it up to a light source to assess its cleanliness and determine whether it needs to be replaced. [3]1

   • If you try to slide the filter out but encounter resistance, there may be a locking mechanism holding it in place. Look for a system like that, then slide the lock aside to let the filter out.

5. 5

   If the filter is too opaque for you to see through, get a new one. When you hold the filter up to a light source and no light comes through, it's time to replace the filter. It's crucial to change the filter frequently to maintain the furnace's proper airflow and prevent it from overheating. [4]1

   • A cardboard frame is present on disposable filters. If the frame of your filter is made of plastic or metal, it is a reusable filter that you can clean as opposed to replacing with a brand-new filter.

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1. 1

   To find the dimensions, look at the cardboard frame of the old filter. Somewhere on the disposable filter's frame will be printed the filter size. Write it down so you can use the measurements as a guide when looking for a new filter. [5]1

   • If the dimensions of your filter are not printed on it, measure it with a measuring tape or look up the manufacturer's recommendations in the owner's manual to make sure you get the appropriate replacement filter.

2. 2

   Buy a replacement filter in the appropriate size. To find a new filter, visit a hardware or home improvement store. Buy a filter that is the same size as the old one by using its measurements as a guide. [6]1

   • Fiberglass filters with cardboard frames are the least expensive disposable furnace filters. This type of filter is intended to be changed every one to two months and will trap large dust particles. A slightly more expensive disposable pleated filter is available if you want to upgrade your filter because it will capture smaller dust, pollen, and dirt particles. These filters have a longer lifespan of four to one year.

   Advice: If you or a member of your family suffers from allergies, you may want to consider purchasing a highly efficient particle air (HEPA) filter. These antimicrobial filters are made specifically to capture contaminants like mold, mildew, fungus, yeast, and algae. Both disposable and reusable options are available.

3. 3

   Look for an arrow on the filter indicating which direction it should face. An arrow on your new filter will indicate which direction the air flows through it. To know which way to slide the filter into your furnace, locate this arrow.

   • In order to prevent collapse or disintegration while trapping dust and other debris, home furnace filters are designed to filter air in a single direction.

4. 4

   Replace any coverings that go over the filter by sliding them into position. The arrow on the new filter should be facing the blower motor of the furnace as you insert it. If you removed one to remove the filter, snap it back into position. [7]1

   • Your furnace won't have enough airflow if you install the filter backwards, and it could overheat and stop working. This may also occur if your filter is dirty, so be sure to check it each month and replace it if necessary.

5. 5

   Furnace door panel should be closed or replaced. Swing the furnace's access door shut, or if you removed it, slide it back on. Now, you can use your furnace for at least another month. [8]1

   • Keep in mind that you should change the filter more frequently if you have furry pets or use your furnace frequently. Every month and whenever you notice dust accumulating in your home, check your filter.

6. 6

   Restart your furnace. Having changed the filter, turn the furnace's thermostat back to the "on" position. The filter will shield your furnace from loose debris, so you can continue using it as usual.

   • If you want to remember to check it again in a month, you might want to make a note of the date you changed the filter.

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