Keeping your furnace filter clean

The job of a furnace filter is to catch dust and dirt. When it gets clogged, the furnace has to work harder, which wastes energy and raises your bills.

Changing or cleaning the filter regularly is one of the simplest ways to save energy.

Air has trouble passing through a dirty filter, so a lot of energy is lost. A clean filter can lower your furnace's energy use by as much as 15%. In the past, disposable filters had to be replaced every two or three months, which produced a great deal of waste.

Today you can buy permanent, washable electrostatic filters, which cut this waste. If your furnace runs a lot, check the filter once a month.

Wash it every two to three months, and keep doing so in summer if you have central air conditioning. Homes with pets may need to clean the filter more often.

Cleaning a reusable filter is easy: rinse it well in the sink or spray it with a garden hose.

For an even greener option, some filters are now made from recycled materials.