Outside Air Filters
This page lists all 12 Outside Air Filters available from Metal Air Filters, manufactured by American Metal Filter Company (AMFCO). Products on this page are HI Series and HIA Series items, precision-engineered for demanding commercial, industrial, and HVAC applications.
AMFCO’s outside air filters are built for long-term performance and reliability. Whether you need permanent washable replacements or specialty filtration products, all items on this page ship directly from our manufacturing facility with full specifications and compatibility documentation.
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Key Benefits of Outside Air Filters
- economizer grade galvanized steel air filter Particulate Filtration: 46% at rated airflow dust arrestance efficiency at 350 fpm rated airflow captures the dust, pollen, insects, and airborne debris characteristic of outside air intake filter streams—providing effective pre-filtration protection for downstream HVAC components including coils, fans, and ductwork in economizer and make-up air intake filter applications without the high pressure drop of MERV-rated filters
- High Dust Holding Capacity: 40 grams per square foot dust holding capacity per unit face area allows extended service intervals in high-loading outside air applications, reducing cleaning frequency and maintenance labor compared to lower-capacity filter types. The corrugated, criss-cross aluminum foil mesh geometry maximizes dust storage volume per inch of filter depth
- permanent washable galvanized steel air filter Design: Rinse with warm water to restore full filtration performance—no replacement media required. The HKG Series washable galvanized steel air filter design eliminates the recurring cost and logistics of disposable filter programs, making it the cost-effective long-term choice for outside air filtration positions with frequent maintenance access
- 200°F Maximum Operating Temperature: Rated for continuous operation at temperatures up to 200°F, making the HKG102025 suitable for rooftop HVAC equipment, make-up air intake filter systems, and outside air handling applications with elevated air temperatures that would damage or degrade lower-rated filter alternatives
- 24 Gauge galvanized steel frame air filter: Precision-mitered 24 gauge galvanized steel frame air filter with pop-rivet corners provides structural rigidity and corrosion resistance in outdoor and semi-outdoor HVAC environments. Drain holes in three frame corners provide condensate relief for installations subject to humid outside air and precipitation. More robust than aluminum for rooftop and outdoor applications with exposure to weather, mechanical handling, and periodic washing
- 30 Gauge Galvanized Steel Face Grids: Galvanized steel face grids on both air entry and exit sides protect the aluminum foil mesh media pack from physical damage during installation, removal, and washing while providing uniform airflow distribution across the filter face at rated 350 fpm velocity
- 3-Ply Corrugated Aluminum Foil Mesh Media: Multiple layers of corrugated aluminum foil mesh assembled in a criss-cross pattern create the extended surface area and tortuous path geometry required for efficient economizer grade galvanized steel air filter particle capture and high dust-holding capacity. The lightweight aluminum foil construction provides excellent corrosion resistance in moisture-laden outside air streams while maintaining the low pressure drop characteristic required for economizer and outside air handling applications
- No Orientation Requirement: Unlike mist eliminator filters that must be installed upright for liquid drainage, the HKG102025 economizer filter installs in vertical or horizontal orientation to suit any housing design and airflow direction—no critical TOP-label requirement
- Made in USA by AMFCO — UL Classified 900: Manufactured by American Metal Filter Company to exacting dimensional and construction standards. UL Classified 900 certification confirms the HKG102025 meets UL’s requirements for air filter unit materials and construction. All 1 Inch nominal sizes available from stock for immediate shipment
Available Outside Air Filters — Complete Product Listing
All 12 outside air filters available from Metal Air Filters, with nominal size, actual dimensions, and current pricing. Click any product for full specifications and purchasing.
| Product / Part No. |
Nominal Size |
Actual Dimensions |
AMFCO SKU |
Price |
| 12x24x1 Washable Aluminum Foil Mesh Air Filter wit |
12x24x1 |
11.5” H × 23.5” W × 7/8″ D (±1/8” H&W, ±1/16” D) |
HKG101224 |
$— |
| 12x24x2 Washable Aluminum Foil Mesh Air Filter wit |
12x24x2 |
11.5” H × 23.5” W × 1-3/4″ D (±1/8” H&W, ±1/16” D) |
HKG201224 |
$— |
| 16x20x1 Washable Aluminum Foil Mesh Air Filter wit |
16x20x1 |
15.5” H × 19.5” W × 7/8″ D (±1/8” H&W, ±1/16” D) |
HKG101620 |
$— |
| 16x20x2 Washable Aluminum Foil Mesh Air Filter wit |
16x20x2 |
15.5” H × 19.5” W × 1-3/4″ D (±1/8” H&W, ±1/16” D) |
HKG201620 |
$— |
| 16x25x1 Washable Aluminum Foil Mesh Air Filter wit |
16x25x1 |
15.5” H × 24.5” W × 7/8″ D (±1/8” H&W, ±1/16” D) |
HKG101625 |
$— |
| 16x25x2 Washable Aluminum Foil Mesh Air Filter wit |
16x25x2 |
15.5” H × 24.5” W × 1-3/4″ D (±1/8” H&W, ±1/16” D) |
HKG201625 |
$— |
| 20x20x1 Washable Aluminum Foil Mesh Air Filter wit |
20x20x1 |
19.5” H × 19.5” W × 7/8″ D (±1/8” H&W, ±1/16” D) |
HKG102020 |
$— |
| 20x20x2 Washable Aluminum Foil Mesh Air Filter wit |
20x20x2 |
19.5” H × 19.5” W × 1-3/4″ D (±1/8” H&W, ±1/16” D) |
HKG202020 |
$— |
| 20x25x1 Washable Aluminum Foil Mesh Air Filter wit |
20x25x1 |
19.5” H × 24.5” W × 7/8″ D (±1/8” H&W, ±1/16” D) |
HKG102025 |
$— |
| 20x25x2 Washable Aluminum Foil Mesh Air Filter wit |
20x25x2 |
19.5” H × 24.5” W × 1-3/4″ D (±1/8” H&W, ±1/16” D) |
HKG202025 |
$— |
| 24x24x1 Washable Aluminum Foil Mesh Air Filter wit |
24x24x1 |
23.5” H × 23.5” W × 7/8″ D (±1/8” H&W, ±1/16” D) |
HKG102424 |
$— |
| 24x24x2 Washable Aluminum Foil Mesh Air Filter wit |
24x24x2 |
23.5” H × 23.5” W × 1-3/4″ D (±1/8” H&W, ±1/16” D) |
HKG202424 |
$— |
Common Specifications — HI Series Aluminum Mesh Filters
The following specifications apply to the HI Series products on this page. Individual products vary by nominal size, actual dimensions, and dust holding capacity — see each product page for complete product-specific specifications.
| Specifications: |
Details: |
| Frame Material |
24 gauge galvanized steel |
| Frame Construction |
Precision-mitered corners secured with pop rivets; drain holes in three frame corners for condensate relief |
| Filter Type |
Economizer grade impingement-type washable galvanized steel framed aluminum foil mesh panel filter |
| Dust Holding Capacity |
40 grams per square foot |
| Rated Airflow |
350 fpm face velocity |
| Recommended Airflow Range |
300–500 fpm |
| Maximum Operating Temperature |
200°F continuous |
| Washability |
Frequent and moderate |
| Compliance & Certifications |
UL Classified 900 |
| Country of Origin |
Made in USA |
Commercial & Industrial Applications
Outside Air Filters from Metal Air Filters are deployed across a wide range of commercial, institutional, and industrial building types. The following applications represent the primary use cases for outside air filters.
The HKG102025 1 Inch aluminum foil mesh economizer filter is engineered for outside air handling applications in commercial, institutional, and light industrial HVAC systems. Its combination of 46% at rated airflow dust arrestance, 40 grams per square foot dust holding capacity, permanent washability, and 200°F temperature rating makes it the practical choice for the high-loading, variable-condition environments encountered in outside air intake filter positions.
Rooftop economizer filter sections and hoods and Outside Air Intakes
Rooftop HVAC units and outside air intake filter systems expose filters to the full range of outdoor airborne contaminants: dust, pollen, insects, leaves, seeds, atmospheric particulate, and in some regions, industrial or agricultural fallout. The HKG102025’s 40 grams per square foot dust holding capacity provides extended service intervals in these high-loading applications, while the galvanized steel frame air filter construction withstands the outdoor environment and mechanical handling associated with rooftop maintenance access. The washable galvanized steel air filter design is particularly cost-effective at rooftop locations where filter changeout involves labor, staging, and waste disposal logistics that disposable filter programs require at each service interval.
make-up air intake filter and Ventilation Systems
make-up air intake filter units introducing 100% outside air into commercial buildings, manufacturing facilities, warehouses, and institutional spaces benefit from the HKG Series economizer filter’s high dust-holding capacity and washability. At 100% outside air, the filter loading rate is substantially higher than mixed recirculating/outside air systems, making the 40 grams per square foot per unit face area capacity and washable galvanized steel air filter design particularly valuable for reducing maintenance frequency and cost. The 200°F temperature rating accommodates make-up air intake filter systems with upstream heating coils or direct-fire heating equipment.
AHU washable aluminum foil mesh pre-filter Positions
air handling unit filter sections with dedicated outside air washable aluminum foil mesh pre-filter sections use economizer grade filters like the HKG102025 to capture coarse outdoor particulate before it reaches downstream MERV-rated filters, coils, and fans. The HKG Series washable aluminum foil mesh pre-filter extends the service life of downstream higher-efficiency filters by intercepting the bulk of the heavy outside air loading at low cost per unit, reducing total filtration system operating cost. The washable galvanized frame construction provides the durability required for AHU washable aluminum foil mesh pre-filter positions where filter housing access may be infrequent and handling conditions variable.
Commercial Building Outside Air Systems
Commercial office buildings, retail facilities, hotels, schools, hospitals, and other commercial building types with mechanical ventilation systems use economizer grade filters at outside air intakes to protect HVAC equipment from the outdoor particulate environment. The HKG102025’s nominal 20x25x1 size fits standard filter tracks and housings in commercial AHUs and rooftop units. The permanent washable galvanized steel air filter design eliminates the recurring cost and waste of disposable filter programs at outside air positions, which require replacement on the same schedule as return air positions despite handling much heavier particulate loads.
Outside Air Filters — Related Search Terms
Customers searching for outdoor air filters will find all matching products on this page. All outside air filters products shown here are manufactured by American Metal Filter Company (AMFCO) as premium washable aluminum mesh filtration products. Whether searching for outdoor air filters by part number, nominal size, or application, each product shown here ships directly from AMFCO with full specifications and compatibility documentation.
Frequently Asked Questions
What are the actual dimensions of the HKG102025?
Actual dimensions: 19.5″ H × 24.5″ W × 0.875″ D (±1/8″ on H&W, ±1/16″ on depth). Nominal size is 20x25x1. The HKG Series uses a 1/2″ undercut on height and width (actual = nominal − 1/2″).
How do I clean the HKG102025 aluminum foil mesh filter?
Rinse with a moderate stream of warm water from the clean side through to the dirty side until water runs completely clear. For heavy loading or grease deposits, a mild detergent solution may be used. Do NOT use high-pressure steam cleaning. Air dry or shake off excess water before reinstalling. The AMFCO tech sheet rates HKG Series washability as frequent and moderate.
Does the HKG102025 have a MERV rating?
No — the HKG102025 HKG Series economizer filter does not carry a MERV rating. It is rated by dust arrestance per ASHRAE 52.1 at 46% at rated airflow at 350 fpm. MERV testing per ASHRAE 52.2 is designed for recirculating air filtration; economizer grade filters for outside air intakes are rated by dust arrestance.
What is the maximum operating temperature of the HKG102025?
The HKG102025 HKG Series is rated for 200°F continuous operation. For higher temperature requirements, AMFCO HM Series filters are rated for 275°F (HMA), 325°F (HMG), and 900°F (HMS).
Can the HKG102025 be installed horizontally or in any orientation?
Yes — the HKG102025 HKG Series economizer filter can be installed in vertical or horizontal orientation. There is no specific orientation requirement. Install in the orientation that suits your housing design and airflow direction. No critical TOP-label-up requirement applies to the HKG Series.
What applications is the HKG102025 designed for?
The HKG102025 is designed for economizer grade outside air applications: rooftop economizer hoods, outside air intake ducts, make-up air systems, and AHU pre-filter positions in commercial and institutional HVAC systems. It is an economizer grade particulate filter, not a mist eliminator or moisture separator.
How does the HKG Series compare to the HKA Series?
HKG (this product): 24 gauge galvanized steel frame and 30 gauge galvanized steel face grids. HKA: aluminum frame and face grids. Both series use aluminum foil mesh media, same nominal depths (1″ and 2″), same arrestance specs, and same economizer grade performance. Frame material is the primary difference — galvanized steel (HKG) for outdoor/rooftop robustness vs aluminum (HKA) for lighter weight and full corrosion resistance.
What is the dust holding capacity of the HKG102025?
The HKG102025 1-inch aluminum foil mesh filter has a dust holding capacity of 40 grams per square foot. This applies to all HKG Series 1-inch nominal standard sizes. The corrugated, criss-cross media assembly maximizes dust storage volume per inch of actual depth for extended service intervals in high-loading outside air applications.
What is the rated airflow for the HKG102025?
The HKG102025 HKG Series is rated at 350 fpm face velocity with a recommended operating range of 300–500 fpm. Note that this is lower than the 500 fpm rating of the HM Series mist eliminators — the HKG Series economizer filter is designed for outside air handling systems operating in the 300–500 fpm range typical of commercial rooftop units and AHU outside air sections.
