Home › Furnace filters › N9MSB / N9MSE
Tempstar N9MSB / N9MSE filter sizes: 14 x 25 x 3/4, 16 x 25 x 3/4, 20 x 25 x 3/4 and 24 x 25 x 3/4, as listed in the Tempstar source document's filter table. Which size fits depends on your cabinet and return. This page is pending human review, so check the source excerpt below.
Auto-extracted · review pending Filter sizes auto-extracted from the manufacturer document.
Last checked against the manufacturer document:
| Sizes found in the source table |
|---|
| 14 x 25 x 3/4 |
| 16 x 25 x 3/4 |
| 20 x 25 x 3/4 |
| 24 x 25 x 3/4 |
Extracted by script from the linked document. Read the excerpt to see which size applies to which cabinet or return.
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.
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.
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.
Manufacturer document for Tempstar N9MSB / N9MSE
Last checked 2026-11-06. Manufacturers revise documents. If your unit's label disagrees, trust the label.
be installed in the common return duct prior to entering the of incorporating a 4-in (102 mm) thick media filter. This allows
return air opening in any orientation. room for future upgrades to other IAQ devices.
See Table 6 for recommended filter size details.
Table 6 Filter Size Information − in. (mm) NOTICE
FURNACE FILTER SIZE
CASING
FILTER Design the duct system FIRST to determine how much
BOTTOM TYPE
WIDTH SIDE RETURN RETURN pressure drop may be allowed in the filter system. See
the AIR DUCTS section. Excessive filter pressure drop
14-3/16 16 x 25 x 3/4 14 x 25 x 3/4
(360) (406 x 635 x 19) (356 x 635 x 19) Washable* often compromises system airflow and duct perform-
17-1/2 16 x 25 x 3/4 16 x 25 x 3/4
ance, causes inadequate airflow to the furthest ends of
(445) (406 x 635 x 19) (406 x 635 x 19) Washable* the duct system, as well as causes excess noise and
16 x 25 x 3/4 20 x 25 x 3/4 higher than anticipated electrical consumption.
21 (533) (406 x 635 x 19) (508 x 635 x 19) Washable*
Provide duct transitions, as required, to smoothly transition
24-1/2 16 x 25 x 3/4 24 x 25 x 3/4 airflow from the return duct system to the filter (or IAQ device)
(622) (406 x 635 x 19) (610 x 635 x 19) Washable*
to the furnace when the dimensions of the ductwork or furnace
* Recommended to maintain air filter face velocity. See Product Data for part
number.
return air opening do not mTempstar N9MSB / N9MSE filter sizes: 14 x 25 x 3/4, 16 x 25 x 3/4, 20 x 25 x 3/4 and 24 x 25 x 3/4, as listed in the Tempstar source document's filter table. Which size fits depends on your cabinet and return. This page is pending human review, so check the source excerpt below. 14 x 25 x 3/4; 16 x 25 x 3/4; 20 x 25 x 3/4; 24 x 25 x 3/4.
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.
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.
Every size found in the source table is 3/4 in. thick: 14 x 25 x 3/4, 16 x 25 x 3/4, 20 x 25 x 3/4 and 24 x 25 x 3/4. Pending human review; check the excerpt.
Manufacturer document for Tempstar N9MSB / N9MSE (https://www.shareddocs.com/hvac/docs/1011/Public/05/44001410103_ICP_25877.pdf), last checked 2026-11-06.