Today is the first of March. If you haven’t changed your furnace filter yet this winter change it today. If you have changed it more recently change it today if it is dirty.
Most of the forced air furnaces I see need a new furnace filter. People don’t seem to understand that the filter needs to be changed on a regular basis. Some filters are supposed to last three months.
When we have weeks of cold weather and the dang thing runs all the time I like to put in a clean filter every month. People who live in warmer climates can probably go for three months.
How do I know mine should be changed every month? I don’t know for sure but it usually looks kind of grey and furry and I would rather err on the side of changing it too soon.
You can buy furnace filters at home improvement stores. I usually buy at least six at a time.
If you don’t know where the filter is or what kind to buy call a heating specialist. There are also some great videos on youtube that will show how to change the filter.
Your furnace has to work harder if the filter is clogged with stuff. That might mean a higher heating bill and it could shorten the life of the fan in your furnace or the furnace itself. A severely clogged filter can cause the furnace to shut down.
The filter on the right in the picture is a new filter. The one on the left is dirty. They can get much dirtier than that. It depends upon how much the furnace is being used rather than just the passage of time.