Carrier Economizer Filters

Carrier Washable Filter — Shop by OEM Part Number

Product Overview — What Are Carrier Economizer Pre-Filters?

Carrier economizers are outside air (OA) intake modules integrated into commercial rooftop units. They allow the HVAC system to draw in cool outdoor air during mild weather, reducing mechanical cooling load and cutting energy costs during shoulder seasons — a process called free cooling or economizer mode. The pre-filter, an aluminum mesh screen mounted directly in the intake louver or dedicated filter track, is the first and only filtration layer between the outdoor environment and the unit’s interior components. It captures large and medium-size particles — pollen, cottonwood seed, insects, leaves, and coarse dust — before they reach the coil, the downstream pleated filters, or the economizer damper blade.

Unlike the disposable filters installed downstream, the economizer pre-filter is designed to be a permanent component. It is a structural and filtration element simultaneously. Carrier’s OEM specification calls for corrugated aluminum mesh media that captures particulate while maintaining a low resistance to airflow across the face. Low pressure drop is critical in high-airflow rooftop applications because any restriction directly increases fan motor load and reduces the volume of supply air delivered to the building below.

Our replacement filters use the same multi-ply corrugated aluminum media construction as the Carrier OEM specification. The media is formed from aluminum alloy corrugated sheet stock, stacked in 5 plies (1” depth) or 7 plies (2” depth), and bonded between two rigid aluminum face grids. Those grids keep the media tightly packed throughout the service life and prevent deformation at high face velocities — a common failure mode in lower-quality aftermarket alternatives fabricated with looser tolerances. The outer frame is .030” nominal wall aluminum alloy, mitered and pop-riveted at the corners to maintain dimensional accuracy to ±1/16” and resist the corrosive outdoor environment of a rooftop installation.

Carrier economizer filters span three primary depth configurations. The 1” depth covers the vast majority of Carrier RTU applications and represents the entire KH03DU and KH03DW series as well as the 50HJ540xxx and 48HG503xxx exact-dimension families. The 2” depth — the KH03HL003 (16×25) and KH03HL005 (20×25) — provides doubled media capacity and extended cleaning intervals for applications with higher dust loading. The 1/2” depth KH03DU267 and KH03DU271 (19-1/2×32) are precision-fabricated exact-dimension filters for specific unit configurations requiring a shallow-depth pre-filter. All three configurations use identical media alloy and frame materials; only the media ply count and dust-holding capacity differ.

Technical Specifications

All Carrier-compatible aluminum mesh filters manufactured by Metal Air Filters conform to the following specifications. Values apply to all depth configurations unless noted.

Carrier OEM Part Number Reference — All Compatible Filters

When ordering a Carrier economizer replacement filter, the most reliable method is matching the OEM part number printed on the existing filter’s frame label or found in the rooftop unit’s maintenance documentation. Carrier uses two primary part number families: the KH03 series covers standard 1”, 2”, and 1/2” depth filters for the majority of WeatherMaker, WeatherExpert, and related RTUs (KH03DU = 1” depth standard sizes; KH03HL = 2” depth; KH03DW = narrow special widths; KH03DU267/271 = 1/2” exact-dimension); the 50HJ540xxx and 48HG503xxx series are exact-dimension filters for specific large-tonnage and legacy commercial unit configurations. The table below maps each Carrier OEM part number to our direct replacement, confirming the filter face size and our catalog SKU.

Not seeing your part number? We manufacture custom-cut filters to exact dimensions — browse our custom filter options or contact us with your filter’s face measurements and depth and we will fabricate to specification.

Finding Your Carrier Economizer Filter Part Number

Before ordering, confirm the replacement filter part number using one of three reliable methods. This prevents incorrect orders in units where multiple filter sizes were used across model years of the same RTU family.

Method 1 — Read the Existing Filter Frame

The OEM part number is typically stamped or heat-stamped directly into the aluminum frame rail on one of the four sides, or printed on a peel-and-stick label adhered to the frame. Look for a prefix of KH03 (standard panel filters), 50HJ (large commercial exact-dimension), or 48HG (legacy commercial) followed by a numeric suffix. If the label is worn, the stamping usually remains readable after wiping with a clean cloth.

Method 2 — Check the Unit Service Label

Many Carrier and Bryant RTUs include a service/maintenance label affixed inside the outside-air (OA) access panel door or on the inside of the unit cabinet directly adjacent to the filter track. This label often lists the required economizer filter part number and nominal filter size. On WeatherMaker 48 and 50 series units, this label is frequently on the inside face of the OA access door. On 50HJ commercial units, check the unit data plate attached to the main cabinet.

Method 3 — Use the Model and Tonnage Reference Table

If the existing filter is missing and no service documentation is available, the compatible models table in the next section maps each Carrier and Bryant RTU family to its typical filter part numbers. Look up your model series and tonnage, then cross-reference with the OEM Part Number table above to confirm the exact face dimensions and depth. Note that some model families used more than one filter size depending on the specific cabinet and economizer configuration — if more than one part number appears for your model series, measure the filter track opening (width × height × depth to the nearest 1/16”) to confirm which size applies.

Compatible Carrier Rooftop Unit Models

Carrier economizer filter part numbers span multiple RTU product families produced over four decades. The KH03DU, KH03HL, and KH03DW filter families serve Carrier and Bryant light-to-mid commercial RTUs — from 3-ton WeatherMaker 48TC installations to 25-ton WeatherExpert 50XCJ configurations; the 50HJ540xxx and 48HG503xxx series are exact-dimension filters for specific large-tonnage commercial platforms. The table below maps each major Carrier and Bryant model family to its typical filter part number(s). The specific size within a family depends on the particular unit’s economizer inlet dimensions — always confirm by checking the part number stamped on the existing filter frame before ordering.

Carrier standardized several economizer filter dimensions across its RTU product line to reduce the number of replacement SKUs required for a full-building maintenance program. A facility with a mixed install of 3-ton and 7.5-ton WeatherMaker units may find that a single KH03DU part number covers multiple units on the roof. Confirming this by checking each unit’s access panel label — which typically identifies the required filter part number or nominal size — takes minutes and significantly simplifies bulk ordering and inventory management.

Note on Bryant compatibility: Bryant and Carrier are sister brands within Carrier Global Corporation. Their commercial rooftop units share engineering platforms, and many Bryant RTUs specify KH03DU-prefix filters dimensionally identical to their Carrier-branded counterparts. If your unit bears the Bryant nameplate and requires a KH03DU, KH03HL, KH03DW, or 50HJ-prefix filter, our replacement is the correct direct fit.

About Carrier — The Inventor of Modern Air Conditioning

Carrier’s origin is one of the most consequential in the history of modern building technology. On July 17, 1902, 25-year-old engineer Willis Haviland Carrier completed the design of the first scientifically engineered air conditioning system for the Sackett-Wilhelms Lithographing and Publishing Company in Brooklyn, New York. The system was designed to control temperature and humidity for printing quality, not human comfort — but its underlying principles, formalized in Carrier’s 1911 paper Rational Psychrometric Formulae, laid the scientific foundation for every air conditioning system that followed. That date is recognized today as the birth of modern air conditioning.

Willis Carrier founded the Carrier Engineering Corporation in 1915 with six fellow engineers, consolidating his work in climate control into a dedicated commercial enterprise. Early milestones included the first air conditioning systems for department stores, movie theaters, and hospitals — establishing the commercial building cooling market that would define 20th-century architecture and urban life. The company’s growth through the 1920s and 1930s cemented its position as the definitive name in commercial HVAC, a distinction that has never been seriously challenged in more than a century of operation.

Carrier became part of United Technologies Corporation (UTC) in 1979, merging into one of the largest industrial conglomerates in the world alongside Pratt & Whitney, Otis Elevator, and Sikorsky Aircraft. Under UTC’s ownership, Carrier expanded its commercial product lines substantially, introducing the packaged rooftop unit families — the 48 and 50 series WeatherMaker and later WeatherExpert — that are still in standard production today. The economizer section, mandated on commercial RTUs by energy codes beginning in the 1970s, introduced the standardized filter track dimensions that the KH03DU, KH03HL, and KH03DW part number families still serve. Bryant HVAC, a Carrier subsidiary since 1955, shares these engineering platforms, which is why Bryant commercial RTUs frequently specify the same KH03-prefix filter part numbers as their Carrier counterparts.

The most recent structural milestone came in April 2020, when UTC separated its climate businesses from the aerospace and elevator divisions, spinning out Carrier Global Corporation as an independent publicly traded company on the New York Stock Exchange under the ticker CARR. The simultaneous merger of UTC’s aerospace and Raytheon created the separate RTX Corporation. The separation returned Carrier to its roots as a focused climate solutions company with the Carrier and Bryant brands, building automation, refrigeration, and fire and security businesses all under one roof. Today, Carrier Global operates manufacturing and service facilities across more than 160 countries, serving commercial building owners, HVAC contractors, building engineers, and facility managers who maintain the hundreds of millions of Carrier and Bryant units installed around the world since the postwar expansion of commercial HVAC.

The KH03DU, KH03HL, KH03DW, 50HJ540xxx, and 48HG503xxx economizer filter part numbers in our catalog correspond to units ranging from 2 to 30 or more years of age — a reflection of Carrier’s large commercial installation base and the decades-long replacement parts lifecycle typical of rooftop HVAC equipment. A Carrier WeatherMaker installed in 2000 may still be drawing air through the same filter track design that Carrier standardized in the 1980s, making proper pre-filter maintenance one of the most cost-effective things a facility manager can do to extend the service life of aging equipment.

Carrier’s commercial HVAC portfolio extends well beyond the packaged rooftop units that dominate the light-to-mid commercial building market. For large central-plant applications, Carrier manufactures the AquaForce and AquaEdge centrifugal water chillers and the 30XA and 61WG air-cooled chiller families, serving mid-rise offices, data centers, hospitals, and university campuses. The Carrier Aero variable refrigerant flow (VRF) line handles multi-zone applications where centralized ductwork is impractical. Carrier’s 39M and 39L custom air handling units (AHUs) provide central distribution backbone for larger institutional buildings. The Fan Coil Unit (FCU) and Chilled Beam product lines round out the terminal-unit portfolio for commercial buildings. Carrier also markets Infinity-series heat pumps and split systems for residential and light commercial applications. Despite this breadth, the packaged rooftop unit — the WeatherMaker and WeatherExpert — remains the highest-volume platform, with tens of millions installed across North America and an ongoing demand for economizer maintenance products that will persist as long as those units remain in service.

Installation Instructions

Installing a replacement Carrier economizer pre-filter is a routine maintenance task that does not require specialized tools or HVAC certifications. Total installation time is typically 10 to 15 minutes per unit, including access panel removal and filter track inspection. The steps below apply to the majority of Carrier and Bryant commercial RTUs equipped with single-piece filter track economizer sections.

Before You Begin

• Confirm the replacement filter dimensions match the existing filter, or verify the OEM part number against the reference table above.
• Follow all jobsite safety protocols for rooftop access, including fall protection appropriate to roof type and parapet height.
• Power down the unit at the main disconnect switch or set the thermostat to off before opening the access panel.
• Have a clean cloth or soft brush available for track cleaning.

Step-by-Step Filter Replacement

1. Access the economizer section by opening the outside air intake access panel. On most Carrier WeatherMaker and WeatherExpert units this panel is on the front face of the unit (the side facing prevailing wind or the unit’s designated outdoor air intake) and is secured with two ¼-turn Dzus fasteners or hex-head screws. A flat-blade screwdriver, Dzus tool, or ¼” hex driver is typically required.
2. Remove the existing filter by gripping the filter frame on both sides and pulling straight out of the filter track. On units equipped with retaining wire clips or a hold-down bar, release those fasteners before pulling. Do not force the filter; if resistance is felt, check for additional fasteners or obstructions.
3. Inspect and clean the filter track. Use a brush or cloth to clear accumulated debris from the four track walls. Inspect for bent sections, corrosion, or gaps that would allow air to bypass the filter face. Any significant track deformation should be corrected before installing the new filter to ensure a bypass-free seal.
4. Slide the new filter into the track with the corrugated media face oriented toward incoming airflow — corrugation rows face the outside of the unit, the flatter face toward the interior. On units with a directional filter track slot, the filter will seat correctly in only one orientation.
5. Confirm full seating. The filter frame should sit flush with the four track walls on all sides. Any gap creates an unfiltered air bypass that defeats the purpose of the pre-filter entirely.
6. Re-engage all retaining fasteners. Replace hold-down bars, retaining clips, or securing screws as applicable. Close and secure the access panel.
7. Restore power and verify normal operation. With the unit back online, confirm that the economizer damper cycles normally. An improperly seated filter with excessive frame interference can restrict damper travel in units where the filter track and damper assembly are closely toleranced.

Model-Specific Access Notes

• WeatherMaker 48TC / 48HC / 48TM (3–7.5 ton): OA access panel is typically on the front face, secured with two Dzus ¼-turn fasteners. Filter slides into a horizontal track just inside the panel opening. The filter frame is relatively lightweight — a single-person job in most conditions.
• WeatherMaker 48DP / 48XP and 50TJ / 50TC / 50XC (7.5–25 ton): Same Dzus panel design as the smaller 48 series. Larger unit sizes may have a taller economizer section requiring a taller filter (20×25 vs. 16×25). Some units in this range use a hold-down retaining wire clipped to the filter track; unhook this clip before removing the filter.
• WeatherExpert 50XCJ / 50XCA (6–25 ton): The WeatherExpert economizer section may be configured differently from the standard WeatherMaker cabinet. Some 50XCJ units use a shallow-depth (1/2”) filter track that accepts the KH03DU267 or KH03DU271 — do not attempt to install a standard 1” depth filter in a 1/2” track. Consult the unit’s installation, operation, and maintenance (IOM) document if access panel location is not immediately apparent.
• 50HJ Commercial Packaged (20–50 ton): These large-tonnage units have substantially heavier access panels and tall economizer sections that may require two people to safely manage. The filter track in some 50HJ configurations spans the full height of the unit face with multiple filter panels. Set up appropriate ladder or lift equipment before beginning; do not reach overhead into a filter track while standing on a ladder without fall protection.
• 48HG Commercial Packaged (15–30 ton): Legacy commercial unit with a similar large-panel access design to the 50HJ. Access is typically from the front of the unit. The 20×24×1 filter (48HG503545) slides into a fixed track — confirm the slot is clear of obstructions before inserting the replacement.
• Bryant 580J / 582J / 585J / 588J: Procedure is identical to the corresponding Carrier WeatherMaker or commercial equivalent. Bryant commercial RTUs share the Carrier cabinet and economizer section design.

Cleaning and Maintenance

Washable aluminum mesh filters are designed to be cleaned and reinstalled rather than discarded, making them both more economical and more environmentally sustainable than disposable alternatives over a multi-year maintenance program. Regular cleaning prevents the filter from reaching the point where pressure differential across a fully loaded media pack is large enough to deform the corrugated layers or push air around the frame seal.

Recommended Cleaning Frequency

A 60 to 90 day interval is a reasonable starting point for standard commercial rooftop installations. Adjust based on site conditions:

• High-particulate sites (highways, agricultural operations, construction zones, heavy vehicular traffic): inspect monthly, clean every 30–60 days.
• Cottonwood or heavy pollen seasons: inspect weekly during peak season. Cottonwood loading can fully block an aluminum mesh filter in 2–3 weeks in affected climates.
• Coastal installations: rinse with fresh water every 60 days to remove salt accumulation even when the filter is not otherwise visibly dirty.
• Low-particulate urban or suburban sites: 90-day intervals are typically sufficient.

Cleaning Procedure

1. Remove the filter from the unit (reverse of installation sequence). Cleaning in place is not recommended as it directs wash water into the economizer section and may wet downstream filters or the coil face.
2. Transport to a suitable cleaning area with hose access or a drain. For high-rise units without rooftop hose access, a wet/dry vacuum handles dry debris removal as an alternative.
3. Rinse with a garden hose or pressure washer on low setting, directing water countercurrent to the original airflow direction — in through the back of the filter, out through the face — to dislodge captured particles rather than driving them deeper into the media layers.
4. For heavy fouling (cottonwood packing, grease-laden intake air, industrial environments): apply a mild detergent or degreaser diluted per the product label, allow a 5-minute dwell, then rinse thoroughly in both directions until rinse water runs clear.
5. Shake excess water from the filter and inspect the frame and media for damage before reinstalling. Look for bent sections, separated corner miters, or media deformation that would create gaps.
6. Allow to air-dry before reinstalling if ambient temperatures are at or below freezing. In warmer conditions, installing a wet filter is acceptable — the unit’s airflow completes the drying within minutes.

When to replace rather than clean: Retire the filter when the aluminum frame shows through-corrosion (pinholes or cracks), when a corner miter has separated beyond re-squaring, or when the media has been physically deformed in a way that creates a persistent bypass gap in the filter track. A filter that still seals cleanly and whose media is physically intact can continue to be cleaned and reinstalled indefinitely within the 5–10 year service life guideline.

Frequently Asked Questions

Are these direct OEM replacements for the original Carrier filters?

Yes. Each filter is manufactured to match the exact dimensional specification of the corresponding Carrier OEM part number, including face dimensions, media depth, and frame wall thickness. Our filters are aftermarket replacements made in the USA by Metal Air Filters and do not carry the Carrier brand name, but dimensional and performance compatibility with the OEM specification is confirmed for every part number listed on this page. The UL 900 Class 1 rating and dust arrestance figures are equivalent to or exceed the original specification.

What is the difference between the KH03DU, KH03HL, and KH03DW designations?

All three are Carrier’s “KH03” kit part number family for economizer pre-filters. KH03DU is the standard 1” depth configuration covering the most common panel sizes (16×20, 16×25, 20×20, 20×25), plus the exact-dimension 1/2” depth KH03DU267 and KH03DU271. KH03HL designates 2” depth filters — same face dimensions as the corresponding KH03DU sizes but with doubled media capacity for higher dust loading applications or extended service intervals. KH03DW covers non-standard narrow widths (8×25 and 8×35) used in specific unit configurations where the standard panel sizes do not fit.

Do these filters fit Bryant rooftop units?

Yes. Bryant and Carrier are sister brands within Carrier Global Corporation. Bryant acquired the Carrier brand relationship in 1955 and has operated on shared engineering platforms ever since. Their commercial rooftop units frequently share filter specifications: if your Bryant unit specifies a KH03DU, KH03HL, KH03DW, or 50HJ-prefix part number, our replacement is a direct dimensional fit. Verify the part number stamped on the existing filter frame before ordering to confirm the exact size required.

How long will a Carrier washable aluminum mesh filter last?

Under normal maintenance conditions — cleaning every 60 to 90 days and frame inspection at each cleaning — these filters deliver a 5 to 10 year service life. The corrugated aluminum media does not degrade from repeated washing or long-term outdoor exposure, and the all-aluminum frame resists typical rooftop corrosion. Retire the filter when the frame shows through-corrosion, a corner joint has separated irreparably, or the media has been physically deformed in a way that creates a persistent bypass gap.

What if my Carrier unit requires a non-standard filter size?

Metal Air Filters manufactures custom-cut aluminum mesh filters to exact face dimensions and depth specifications. If your economizer requires a size not shown in our standard catalog — including fractional-dimension filters and sizes larger than our listed stock — contact us with the exact face measurements (height × width × depth to the nearest 1/16”) and we will fabricate to specification from the same UL 900 Class 1 rated materials used in our standard catalog products.

Can I wash the filter while it is still installed in the unit?

We recommend removing the filter for cleaning rather than washing it in place. In-place washing directs water into the economizer section, potentially wetting the downstream pleated or MERV-rated filters and the coil face. Wet downstream filters can collapse or lose structural integrity, and wetting an evaporator coil in freezing conditions can cause ice formation that damages the aluminum fins. Filter removal adds roughly 5 minutes to the process and allows for thorough rinsing from both sides, complete inspection, and proper drying assessment before reinstallation.

Are these filters rated for continuous outdoor exposure?

Yes. The corrugated aluminum media and aluminum alloy frame are both specified for outdoor service as required by the rooftop economizer application. The UL 900 Class 1 rating confirms flame-spread characteristics appropriate for air-handling applications, and the 275°F continuous temperature rating far exceeds any temperature encountered in a rooftop economizer intake under normal operating conditions. In severe coastal or industrial chemical environments, inspect the frame more frequently for accelerated corrosion and plan for replacement at the lower end of the 5–10 year service life guideline.

What is the difference between KH03DU267 and KH03DU271?

Both KH03DU267 and KH03DU271 are exact-dimension filters measuring 19-1/2” × 32” × 1/2” (19.50 × 32.00 × 0.50 nominal). They represent two different Carrier OEM service part number revisions for the same physical configuration — a common practice across all major HVAC manufacturers when service documentation is updated without a dimensional change to the underlying component. Both replacements in our catalog are manufactured to the identical 19-1/2 × 32 × 1/2” specification and are interchangeable in the same filter track. If your unit’s documentation specifies either number, the corresponding replacement is the correct choice.

Do these filters work in Carrier heat pump packaged units (50DJ / 50DZ / 50JQ)?

Yes. Carrier heat pump packaged units — including the 50DJ, 50DZ, 50JQ, and related heat pump RTU families — use the same economizer section and filter track geometry as their cooling-only WeatherMaker counterparts. The required KH03DU or KH03HL filter part number is determined by the specific unit’s economizer inlet dimensions, which are the same regardless of whether the unit provides cooling only or heating and cooling via a heat pump refrigeration circuit. Identify your replacement by the OEM part number on the existing filter frame or the unit’s service label, then select from the reference table above.