18 × 24 Filters | McMaster-Carr

The pleats create a large surface area for filtering without reducing airflow. These filters are typically used as replacement filters in HVAC equipment. The cardboard frame is treated to resist humidity, and the galvanized steel grill prevents sagging.

These filters meet UL 900 flame retardance requirements. Actual size is up to 5/8” less than trade size.

Don’t see the size you need? Additional sizes are available.

For technical drawings and 3-D models, click on a part number.

1" Thick

		Filter Efficiency @
HVAC Filter Trade Size	MERV Filter Rating	1 Micron	3 Microns	Removes Particle Size Down To, microns	Material	Frame Material	Max. Temp., °F		Pkg.
Pkg. of 2
18 × 24	8	44%	73%	3	Polyester Plastic/Polyethylene Plastic Blend	Cardboard	180°	00000000	000000
Pkg. of 12
18 × 24	8	44%	73%	3	Polyester Plastic/Polyethylene Plastic Blend	Cardboard	180°	00000000	00000

2" Thick

		Filter Efficiency @
HVAC Filter Trade Size	MERV Filter Rating	1 Micron	3 Microns	Removes Particle Size Down To, microns	Material	Frame Material	Max. Temp., °F		Pkg.
Pkg. of 2
18 × 24	8	44%	73%	3	Polyester Plastic/Polyethylene Plastic Blend	Cardboard	180°	00000000	000000
Pkg. of 12
18 × 24	8	44%	73%	3	Polyester Plastic/Polyethylene Plastic Blend	Cardboard	180°	00000000	000000

4" Thick

		Filter Efficiency @
HVAC Filter Trade Size	MERV Filter Rating	1 Micron	3 Microns	Removes Particle Size Down To, microns	Material	Frame Material	Max. Temp., °F		Pkg.
Pkg. of 2
18 × 24	8	44%	73%	3	Polyester Plastic/Polyethylene Plastic Blend	Cardboard	180°	00000000	000000
Pkg. of 6
18 × 24	8	44%	73%	3	Polyester Plastic/Polyethylene Plastic Blend	Cardboard	180°	00000000	000000

Mildew-Resistant Pleated Panel Air Filters

A compound inhibits mildew and mold growth. All of these filters have pleats that create a large surface area for filtering without reducing airflow. They meet UL 900 flame retardance requirements. Actual size is up to 5/8” less than trade size.

Product registration requirements restrict sales to the listed areas.

For technical drawings and 3-D models, click on a part number.

1" Thick

		Filter Efficiency @
HVAC Filter Trade Size	MERV Filter Rating	1 Micron	3 Microns	Removes Particle Size Down To, microns	Frame Material	Max. Temperature, °F	Cannot Be Sold To		Pkg.
Pkg. of 1
Synthetic Fiber
18 × 24	8	20%	70%	3	Cardboard	150°	Canada	00000000	000000
Pkg. of 12
Synthetic Fiber
18 × 24	8	20%	70%	3	Cardboard	150°	Canada	00000000	000000

2" Thick

		Filter Efficiency @
HVAC Filter Trade Size	MERV Filter Rating	1 Micron	3 Microns	Removes Particle Size Down To, microns	Frame Material	Max. Temperature, °F	Cannot Be Sold To		Pkg.
Pkg. of 1
Synthetic Fiber
18 × 24	8	20%	70%	3	Cardboard	150°	Canada	00000000	000000
Pkg. of 12
Synthetic Fiber
18 × 24	8	20%	70%	3	Cardboard	150°	Canada	00000000	000000

Panel Air Filters

These filters are typically used as replacements in HVAC equipment.

All meet UL Classified flame retardance requirements. Actual size is up to 5/8” more or less than trade size.

Prefilters can be used as a standalone filter or a prefilter that guards your main filter. They’re an economical choice for protecting expensive filters that catch fine particles.

For technical drawings and 3-D models, click on a part number.

Prefilters
HVAC Filter Trade Size	MERV Filter Rating	Filter Efficiency @ 3 Microns	Removes Particle Size Down To, microns	Material	Frame Material	Max. Temp., °F	Pkg. Qty.		Pkg.
1" Thick
18 × 24	5	20%	3	Fiberglass	Cardboard	180°	12	0000000	000000
2" Thick
18 × 24	5	20%	3	Fiberglass	Cardboard	180°	12	0000000	00000

Heavy Duty Reusable Metal Panel Filters

With a frame made of a thick gauge metal, these filters are durable. They can be washed and reused. Also known as metal mesh filters.

All meet UL 900 flame retardance requirements.

Don’t see the size you need? Additional sizes are available.

For technical drawings and 3-D models, click on a part number.

1" Thick
HVAC Filter Trade Size	MERV Filter Rating	Removes Particle Size Down To, microns	Material	Frame Gauge	Max. Temperature, °F		Each
18 × 24	4	10	Aluminum	18	240°	0000000	000000
2" Thick
18 × 24	4	10	Aluminum	18	240°	00000000	00000

Ultra-Efficiency Panel Air Filters

Rated MERV 13, these filters capture particles down to 0.3 microns. Use in data centers, hospitals, and other locations that require extra-clean air. These filters have pleats that create a large surface area for filtering without reducing airflow. The cardboard frame is treated to resist humidity, and the galvanized steel grill prevents sagging.

Filters meet UL 900 flame retardance requirements. Actual size is up to 5/8" less than trade size.

For technical drawings and 3-D models, click on a part number.

1" Thick

		Filter Efficiency @
HVAC Filter Trade Size	MERV Filter Rating	0.3 Microns	1 Micron	3 Microns	Removes Particle Size Down To, microns	Material	Frame Material	Max. Temp., °F		Pkg.
Pkg. of 2
18 × 24	13	50%	85%	90%	0.3	Polyethylene Plastic/Polypropylene Plastic Blend	Cardboard	150°	00000000	000000
Pkg. of 12
18 × 24	13	50%	85%	90%	0.3	Polyethylene Plastic/Polypropylene Plastic Blend	Cardboard	150°	00000000	000000

2" Thick

		Filter Efficiency @
HVAC Filter Trade Size	MERV Filter Rating	0.3 Microns	1 Micron	3 Microns	Removes Particle Size Down To, microns	Material	Frame Material	Max. Temp., °F		Pkg.
Pkg. of 2
18 × 24	13	50%	85%	90%	0.3	Polyethylene Plastic/Polypropylene Plastic Blend	Cardboard	150°	00000000	000000
Pkg. of 12
18 × 24	13	50%	85%	90%	0.3	Polyethylene Plastic/Polypropylene Plastic Blend	Cardboard	150°	00000000	000000

4" Thick

		Filter Efficiency @
HVAC Filter Trade Size	MERV Filter Rating	0.3 Microns	1 Micron	3 Microns	Removes Particle Size Down To, microns	Material	Frame Material	Max. Temp., °F		Pkg.
Pkg. of 2
18 × 24	13	50%	85%	90%	0.3	Polyethylene Plastic/Polypropylene Plastic Blend	Cardboard	150°	00000000	000000
Pkg. of 6
18 × 24	13	50%	85%	90%	0.3	Polyethylene Plastic/Polypropylene Plastic Blend	Cardboard	150°	00000000	000000

High-Efficiency Panel Air Filters

Rated MERV 11, these filters capture particles down to 1 micron. Use in data centers and other locations that require extra-clean air. These filters have pleats that create a large surface area for filtering without reducing airflow. The cardboard frame is treated to resist humidity, and the galvanized steel grill prevents sagging.

These filters meet UL 900 flame retardance requirements. Actual size is up to 5/8" less than trade size.

For technical drawings and 3-D models, click on a part number.

1" Thick

		Filter Efficiency @
HVAC Filter Trade Size	MERV Filter Rating	0.3 Microns	1 Micron	3 Microns	Removes Particle Size Down To, microns	Material	Frame Material	Max. Temperature, °F		Pkg.
Pkg. of 2
18 × 24	11	20%	65%	85%	1	Polyethylene Plastic/Polypropylene Plastic Blend	Cardboard	150°	0000000	000000
Pkg. of 12
18 × 24	11	20%	65%	85%	1	Polyethylene Plastic/Polypropylene Plastic Blend	Cardboard	150°	000000	000000

2" Thick

		Filter Efficiency @
HVAC Filter Trade Size	MERV Filter Rating	0.3 Microns	1 Micron	3 Microns	Removes Particle Size Down To, microns	Material	Frame Material	Max. Temp., °F		Pkg.
Pkg. of 2
18 × 24	11	20%	65%	85%	1	Polyethylene Plastic/Polypropylene Plastic Blend	Cardboard	150°	0000000	000000
Pkg. of 12
18 × 24	11	20%	65%	85%	1	Polyethylene Plastic/Polypropylene Plastic Blend	Cardboard	150°	0000000	000000

4" Thick

		Filter Efficiency @
HVAC Filter Trade Size	MERV Filter Rating	0.3 Microns	1 Micron	3 Microns	Removes Particle Size Down To, microns	Material	Frame Material	Max. Temp., °F		Pkg.
Pkg. of 2
18 × 24	11	20%	65%	85%	1	Polyethylene Plastic/Polypropylene Plastic Blend	Cardboard	150°	00000000	000000
Pkg. of 6
18 × 24	11	20%	65%	85%	1	Polyethylene Plastic/Polypropylene Plastic Blend	Cardboard	150°	00000000	000000

High-Efficiency Long-Life Panel Air Filters

With tight pleats, these filters have a larger surface area than filters with standard pleats for improved efficiency and an even longer life. These filters strike a good balance of filtering efficiently while allowing airflow, making them a more cost-effective option than higher rated filters. All are effective at capturing common allergens such as dander, mold spores, and pollen. Use them in data centers and other locations that require extra-clean air.

For technical drawings and 3-D models, click on a part number.

		Filter Efficiency @
HVAC Filter Trade Size	MERV Filter Rating	0.3 Microns	1 Micron	3 Microns	Removes Particle Size Down To, microns	Material	Frame Material	Max. Temperature, °F		Each
2" Thick
18 × 24	11	20%	65%	85%	1	Fiberglass	Plastic	175°	0000000	000000

Strong-Odor-Removal Panel Air Filters

Eliminate heavy odors with these filters that have 30 times the odor removing ability of standard odor-removal air filters. The cardboard frame is treated to resist humidity, and the galvanized steel grill prevents sagging.

These filters meet UL 900 flame retardance requirements. Actual size is up to 5/8" less than trade size.

For technical drawings and 3-D models, click on a part number.

2" Thick
HVAC Filter Trade Size	MERV Filter Rating	Filter Efficiency @ 3 Microns	Removes Particle Size Down To, microns	Carbon Concentration, g/sq. ft.	Material	Frame Material	Max. Temperature, °F		Each
18 × 24	7	50%	3	300	Carbon-Filled Polyester Plastic	Cardboard	120°	0000000	0000000

Frames for Panel Air Filters

Hold panel filters in place. The frames can be welded together to hold multiple filters. The trade size is the actual size of the frame.

Add clips to attach frames to 1" or 4" filters.

For technical drawings and 3-D models, click on a part number.

Frames

Frame

Replacement Retaining Clip

Frames								Replacement Retaining Clips
For HVAC Filter Trade Size	For Filter Thick.	Frame Material	Frame Gauge	Mounting Hardware Included	Includes		Each	Pkg. Qty.		Pkg.
18 × 24	2"	Galvanized Steel	16	Yes	Retaining Clips, Sealing Gasket	000000000	000000	2	00000000	00000

Optional Clips

Optional Clip

For Filter Thickness	Material	Pkg. Qty.		Pkg.
1"	Galvanized Steel	2	00000000	00000
4"	Galvanized Steel	2	00000000	0000