Lennox furnace filter replacement

Find the exact replacement filter for your Lennox HVAC system. All sizes available in MERV 8, 11, and 13.

How to find your Lennox filter size: Check the cardboard edge of your existing filter — the size is printed on the frame. It reads like "16x20x1". Match that exactly when ordering.

Most common Lennox filter sizes

16×25×1"
Actual: 15.5×24.5×0.75"
MERV 8 from $8.77/ea MERV 11 from $10.53/ea MERV 13 from $12.46/ea
20×25×1"
Actual: 19.5×24.5×0.75"
MERV 8 from $10.97/ea MERV 11 from $13.16/ea MERV 13 from $15.57/ea
16×20×1"
Actual: 15.5×19.5×0.75"
MERV 8 from $7.02/ea MERV 11 from $8.42/ea MERV 13 from $9.97/ea

Don't see your exact size?

Use the size finder — enter your exact dimensions and we'll show you all available options.

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About Lennox air filters

Lennox HVAC systems use standard pleated air filters in nominal sizes. The most common Lennox filter sizes are 16x25x1, 20x25x1, 16x20x1, though exact sizes vary by model. Always check your existing filter or your owner's manual to confirm the correct size before ordering.

For most Lennox residential systems, a MERV 8 filter provides the right balance of filtration and airflow. Homes with pets or mild allergies may benefit from MERV 11. MERV 13 provides the highest filtration but may slightly reduce airflow on some systems — check your manual if unsure.

How often to change your Lennox filter: Every 90 days for a 1-inch filter, every 6–12 months for 4-inch and 5-inch media filters. Set a free reminder and we'll email you when it's time.

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