While as little as 20 years ago, cabin air filters were only found in higher end cars, today pretty much anything on four wheels has one of these paper elements to help keep air-borne impurities out.

Dryers that don’t dry, vacuum cleaners that don’t clean, and air conditioners that don’t cool might be plagued by the same problem: a clogged or dirty filter. To keep many appliances in tip-top shape, ...

Running your furnace, central air, or heat pump probably constitutes a big part of your utility bill. But it’s a small, often inexpensive part—the air filter—that keeps these heating and cooling ...