Furnace filters must be changed regularly to maintain the efficiency of your furnace and to prevent dust from spreading through your house.
Standard furnace filters (figure A) should be changed at least once per month. Electrostatic disposable filters (figure B), which use static electricity to attract dust, may be used for as long as three months.
You might find it more cost-effective to install a reusable electrostatic filter (figure C) that can be cleaned and reused. To clean your reusable filter, spray it from behind with a garden hose, or blow compressed air through it from behind. If you disassemble your filter before cleaning it, lay out the pieces in the order you remove them so you'll know how to put them back together.
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