To keep your furnace running as efficiently as possible, it is important to regularly change the air filter. This guide is about changing a furnace filter.
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I could never remember for sure when I changed my A/C furnace filter, so now I write the date I need to replace it on the filter with a permanent marker. Works great! No more trying to remember!
By Barbara from Columbia, KY
Save on heating/cooling costs by maintaining your air filter. A heating system repairman told me to use the cheapest, blue filter, and to change it at least monthly or when soiled. He told me this would let the air conditioning motor work much more easily, saving electricity and extending the life of the air conditioner.
If you have a 14x20 inch opening, you can buy a 30x20 inch filter and make 2 from them. Get the wire-supported corrugated white filter. Cut the supporting cardboard at 15 inches. Cut the filter to size, and fold the cardboard supports back 1 inch to support the filter. Make sure the edge meets the opening. Now you have 2 filters.
By Nance from Statesboro, GA
To save on your electric bill and to make your air conditioner compressor last longer, keep your furnace filters clean. We put a post-it note on the furnace door with the date we last cleaned them.
By Terri H.
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Here are questions related to Changing a Furnace Filter.
I'm hoping someone can settle a dispute between my husband and I. I really just want him to see it in print, then maybe it'll sink in. How often does everyone change their furnace filter during the winter months? He changes ours twice a year and really honestly believes that it is often enough. I say it should be every month during November to April. What do you think? I'll show him all responses.
Sandy from Pittsburgh, PA
By realist 01/12/2015
Keep in mind: It is a complete myth that when a partially clogged filter begins to slow down the airflow, the fan will "work harder to try to maintain airflow". Fans don't try to maintain airflow. They have no will. In the real world, squirrel cage fans actually work harder when they are moving air freely. If you completely block the airflow, the fan will spin faster because it's easier to just spin the air around in its chamber than to move large quantities of air. It doesn't spin faster because it's "trying harder". There are good reasons to change filters, but saving electrical energy from fan use is simply not one of them.
I live in a mobile home and have a Coleman heat and air unit; it is all electric. My home is very dusty, yet every time I change the filter there's not a speck of dust on it.
By Abigail A.  12/28/2014
I don't think your fan is working properly. Is it heating well? My filters are always covered with dust, and the fan itself will get clogged with it. Turn your furnace off and check to see if the fan is clogged.
I don't know how to change my furnace filter. What do I do?
By Sharon from Cudahy, WI
There's a 'door' on one of the sides of the furnace itself. Open that and you'll easily be able to figure out how to slide the filter out. Check the measurement written on the filter edges so you'll know exactly what size to buy to replace the old one.
My furnace filter is between the furnace and the humidifier. The filter is installed upright. Should the arrow point to the furnace or to the humidifier? I don't know where the furnace blower is.
By Jean H.