Tag Archives: Furnace filter

Eco-Saturday: Change your furnace filter

The old filter, left, and new one, right.
The old filter, left, and new one, right. Photo by Ron, who was kind enough to snap a quick iPhone picture last time he swapped out our filter.

Changing your furnace filter isn’t the most glamorous or visually stimulating Eco-Saturday tip you’ll ever get, but it’s an important bit of home maintenance that really shouldn’t be neglected.

A filter clogged with dirt, pet hair and other debris limits the amount of air moving through your furnace, forcing the blower to work harder, dragging down the energy efficiency and potentially shortening the life of your system.

If you’ve never changed the filter, go look at your furnace. Locate the existing filter (you’re looking for something that resembles the end of a long, flat cardboard box) and pull it out. Printed somewhere along one edge will be the dimensions — a series of three numbers telling you the length, width and thickness of the filter. Write down the numbers.

Put the filter back and go to the hardware store. Most hardware stores carry approximately forty-eleven billion different types of filters. If you have allergies, look for one designed to filter out allergens. If you don’t have allergies, buy whatever’s cheap; the differences in quality aren’t significant enough to make the expensive kind worth the extra money unless you have serious issues with indoor air quality. The important thing is to get the right dimensions, which is why you wrote down the numbers on your old filter. If those numbers don’t match, the filter isn’t going to fit right or function properly in your system.

Take your new filter home, pull out the old one, and put the new one in its place.

If you need a visual, here’s a pretty good YouTube video on the subject:

That’s all there is to it. The whole job takes about two minutes (20 if you count the time you spend going to the hardware store) and will save you a lot of money on energy costs. We change ours every season — the same time we test our smoke detector batteries and change the water filter on our kitchen faucet, which helps us remember to do it.

Emily