DIY guideFurnace

Replace a furnace filter

Slide out the old filter and slide in a fresh one, its arrow pointing the right way.

7 steps

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Set the thermostat to Off, so the fan isn't running while the filter is out.
Look where the big return duct meets the furnace, often a slot with a cover near the bottom. In some homes it's behind a grille on a wall or ceiling instead.
With a fan coil or an air handler, the filter often sits behind a return grille on a wall or the ceiling. Undo the grille's latches and it swings open, the filter right behind it.
Pull it straight out. Note the size printed on its edge, and which way its arrow points.
Put the new filter in with its arrow pointing toward the furnace, the way the air flows.
A reusable filter says so on its frame. Rinse it with a hose or in a tub until the water runs clear, let it dry completely, then slide it back in with the arrow toward the furnace.
Close the cover and set the thermostat back. Check the filter every month: thin filters usually last one to three months, so follow the time on its package.

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