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Carrier 59MN7C gas furnace: filter size

The Carrier 59MN7C gas furnace uses a 16 x 25 x 3/4, 20 x 25 x 3/4 or 24 x 25 x 3/4 filter, depending on cabinet width (or model) and return location (per the Carrier document cited on this page). The table below shows which size applies to each cabinet and return.

Verified from manufacturer doc Modulating condensing gas furnace, 4-way multipoise (no internal filter rack)

Last checked against the manufacturer document:

Applies to

Model numbers printed in the linked Carrier document:

59MN7C060C17--14, 59MN7C060C21--20, 59MN7C080C17--14, 59MN7C080C21--20, 59MN7C100C21--22, 59MN7C120C24--22

Filter sizes by cabinet / model

Casing widthSide returnBottom return
17-1/2 in.16 x 25 x 3/416 x 25 x 3/4
21 in.16 x 25 x 3/420 x 25 x 3/4
24-1/2 in.16 x 25 x 3/424 x 25 x 3/4

Optional filter cabinet (same document): 16 in. cabinet – (1) 16 x 25 x 3/4 washable or (1) 16 x 25 x 4-5/16 media; 20 in. – (1) 20 x 25 x 3/4 or (1) 20 x 25 x 4-5/16; 24 in. – (1) 24 x 25 x 3/4 or (1) 24 x 25 x 4-5/16.

Close-up of a pleated furnace air filter
Illustration only. Not this manufacturer's part.

Replacement interval

General guidance (not from this manual): check monthly and replace 1-in. filters every 1–3 months, or follow the filter maker's guidance and your owner's manual.

Before you buy

Pull the old filter and read the size printed on its frame. Nominal sizes are rounded up: a 15.5 x 24.5 in. filter is sold as 16 x 25.

Buy

Match the size or part number printed on your current filter.

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MERV notes

Your furnace manual lists the filter's dimensions, not its MERV rating. Higher-MERV filters restrict more air. Manufacturers such as Carrier recommend keeping the clean-filter pressure drop under 0.2 in. w.c. (ideally under 0.1). Lennox warns that an over-restrictive filter can trip the high limit in winter and freeze the coil in summer. If you want MERV 11–13, a 4-in. media cabinet is the usual route. Ask an HVAC tech to check static pressure. Nominal sizes are rounded: a filter labeled 16 x 25 x 1 actually measures about 15.5 x 24.5 x 0.75.

Related models

Where this data came from

Installation Instructions 59MN7C-04SI, Table 7 – Filter Information
Last checked 2026-10-26. Manufacturers revise documents. If your unit's label disagrees, trust the label.

FAQ

What size filter does the Carrier 59MN7C gas furnace use?

The Carrier 59MN7C gas furnace uses a 16 x 25 x 3/4, 20 x 25 x 3/4 or 24 x 25 x 3/4 filter, depending on cabinet width (or model) and return location (per the Carrier document cited on this page). The table below shows which size applies to each cabinet and return. 17-1/2 in. – 16 x 25 x 3/4 – 16 x 25 x 3/4; 21 in. – 16 x 25 x 3/4 – 20 x 25 x 3/4; 24-1/2 in. – 16 x 25 x 3/4 – 24 x 25 x 3/4.

How often should I replace the Carrier 59MN7C gas furnace filter?

General guidance (not from this manual): check monthly and replace 1-in. filters every 1–3 months, or follow the filter maker's guidance and your owner's manual.

Why doesn't my filter measure exactly 16 x 25?

Filter sizes are nominal (rounded). A filter sold as 16 x 25 x 1 actually measures about 15.5 x 24.5 x 0.75 in. Buy by the nominal size printed on the frame.

What is the Carrier 59MN7C gas furnace side return filter size?

Side return filter size by casing width: 17-1/2 in.: 16 x 25 x 3/4; 21 in.: 16 x 25 x 3/4; 24-1/2 in.: 16 x 25 x 3/4 (per the source table).

What is the Carrier 59MN7C gas furnace bottom return filter size?

Bottom return filter size by casing width: 17-1/2 in.: 16 x 25 x 3/4; 21 in.: 20 x 25 x 3/4; 24-1/2 in.: 24 x 25 x 3/4 (per the source table).

Where does this information come from?

Installation Instructions 59MN7C-04SI, Table 7 – Filter Information (https://www.shareddocs.com/hvac/docs/1009/Public/09/59MN7C-04SI.pdf), last checked 2026-10-26.