Product details
Per Koch Bulletin K985-A, the Koch Permanent Aluminum Washable Filter is a completely washable, reusable air filter designed for air or grease applications. Per Koch K985-A, Type MA all-aluminum filters offer all the advantages of the standard metal filter with the added advantage of being extremely lightweight. The filters consist of aluminum cloth secured by expanded aluminum mesh. Per Koch K985-A, "this media has excellent dirt holding properties because of its large surface area." A durable all-aluminum frame encloses the media and provides longlasting support.
What you get: washable metal-frame filters, sold by the case
Each variant is a complete metal-frame washable filter sized for standard HVAC and grease-application openings. Available in 1″ and 2″ depths, sold by the case in the carton quantities shown:
-
1″ depth filters:
- 16″x20″x1″ — 12 filters per case
- 16″x25″x1″ — 12 filters per case
- 20″x20″x1″ — 12 filters per case
- 20″x25″x1″ — 12 filters per case
- 24″x24″x1″ — additional size — 12 filters per case
-
2″ depth filters:
- 16″x20″x2″ — 12 filters per case
- 16″x25″x2″ — 12 filters per case
- 20″x20″x2″ — 12 filters per case
- 20″x25″x2″ — 12 filters per case
- 24″x24″x2″ — additional size — 12 filters per case
Custom and additional sizes (such as 24″x24″ in 1″ and 2″ depths) are available beyond the K985-A published table. Per Koch K985-A, "Please consult the factory for other sizes and configurations."
About the handles you see in product photos
The pictured filter shows bail handles, but filters ship without handles by default. Per Koch K985-A: "Filters are furnished without handles, but both bail and ring types are available upon request." If your application needs handles — for frequent removal in commercial kitchen exhaust hoods, equipment access panels, or any setting where the filter is pulled and washed often — contact RTF support before ordering and we'll arrange handles (bail or ring) on your case. Just let us know which handle type and how many filters need them.
Permanent Aluminum Filter construction (per Koch K985-A)
- Material: Aluminum
- Koch product type: Type MA (Bulletin K985-A)
- Media: Aluminum cloth secured by expanded aluminum mesh (per Koch K985-A)
- Frame: Durable all-aluminum frame
- Weight advantage: Per Koch K985-A, "extremely lightweight" while retaining all advantages of standard metal filters
- Dirt holding: Per Koch K985-A, "excellent dirt holding properties because of its large surface area"
- Reusable: Completely washable (per Koch K985-A)
- Available depths: 1″ and 2″ (in this RTF lineup); 4″ depth available on request per Koch K985-A
- Handles: Filters ship without handles by default. Bail or ring handles available on request — see "About the handles you see in product photos" above, or contact RTF support before ordering.
- Doubled airflow option: Per Koch K985-A, "Both steel and aluminum filters can be operated at twice the CFM capacities listed above, with corresponding increases in pressure drop." (Steel and aluminum specifically; consult Koch for stainless.)
- 1/8″ and 3/8″ depths: Available on request — request a quote for these custom-thin variants.
Published performance data (per Koch K985-A, Type MA)
The following table reproduces Koch K985-A's published performance data for the Aluminum Permanent Filter line at the sizes carried in this RTF lineup:
| Nominal Size | Actual Size | Rated CFM | Initial Resistance | Average Arrestance |
|---|---|---|---|---|
| 16″x20″x1″ | 15.50 x 19.50 x 0.875″ | 640 | 0.035″ w.g. | 72% |
| 16″x25″x1″ | 15.50 x 24.50 x 0.875″ | 800 | 0.030″ w.g. | 72% |
| 20″x20″x1″ | 19.50 x 19.50 x 0.875″ | 800 | 0.030″ w.g. | 72% |
| 20″x25″x1″ | 19.50 x 24.50 x 0.875″ | 1000 | 0.030″ w.g. | 72% |
| 16″x20″x2″ | 15.50 x 19.50 x 1.75″ | 640 | 0.050″ w.g. | 72% |
| 16″x25″x2″ | 15.50 x 24.50 x 1.75″ | 800 | 0.050″ w.g. | 72% |
| 20″x20″x2″ | 19.50 x 19.50 x 1.75″ | 800 | 0.050″ w.g. | 72% |
| 20″x25″x2″ | 19.50 x 24.50 x 1.75″ | 1000 | 0.050″ w.g. | 72% |
Average Arrestance is reported per ASHRAE 52.1 (older standard); these permanent metal filters are positioned as equipment protection and grease capture rather than fine particulate filtration.
Cleaning and maintenance (per Koch K985-A)
Per Koch K985-A, the Permanent Metal Washable Filter is designed for in-service cleaning rather than disposal-and-replace. Koch's published maintenance procedure:
- Wash: Per Koch K985-A, "Simply wash away dirt with hose or soapy water."
- Re-coat with adhesive: Per Koch K985-A, "Recoat with adhesive spray before re-using."
This permanent design is what gives metal filters their cost advantage over disposable filters — one filter, washed and recoated as needed, replaces many disposable filter changes over its service life.
Air or grease applications (per Koch K985-A)
Per Koch K985-A, Permanent Metal Washable Filters are specified for both air and grease applications. This dual-application capability reflects two main use cases:
- HVAC air filtration: Equipment protection and primary particulate capture in commercial and residential HVAC systems where reusable filtration is preferred over disposable filters — especially in dusty environments where rapid loading would shorten disposable filter life.
- Commercial kitchen exhaust: Range hoods, grill hoods, and other foodservice exhaust applications where grease-laden vapor must be filtered before exhaust ductwork. The metal frame and washable construction handle the high-temperature, grease-saturated airstream that would destroy fiber-based filters. Required in many jurisdictions for foodservice fire-safety compliance.
About permanent metal washable filters
Permanent metal filters trade off particulate efficiency (the average arrestance values are in the 71–76% range per Koch K985-A) for two critical advantages over disposable filters: reusability (washable cycles instead of replacement) and grease/temperature tolerance (metal mesh stands up to grease and heat that would saturate or melt fiber media). For applications where fine particulate filtration is the goal — office HVAC, sensitive equipment, indoor air quality — you'll want a higher-efficiency disposable pleated filter (MERV 8+) instead. For equipment protection, primary capture, kitchen exhaust, and any setting where filter changes need to be infrequent, permanent metal filters are the right specification.
Sizing and ordering notes
- Match nominal size to your filter slot. Per Koch K985-A, actual size for 1″ nominal-depth filters is 0.875″ (7/8″) deep, and actual size for 2″ nominal-depth filters is 1.75″ (1-3/4″) deep.
- Each variant ships in the case quantity shown. Order multiple cases by adjusting the quantity at checkout.
- Custom thin filters: 1/8″ and 3/8″ depths are available on request from Koch.
- Need handles? Filters ship without handles by default. Bail or ring handles available on request — contact RTF support before placing your order so we can arrange handles on your case.
- For grease/kitchen applications: Replace or wash on your maintenance schedule per local fire code requirements (typically 30 days for active foodservice).
- Cleaning: Per Koch K985-A, hose or soapy water; recoat with adhesive spray before re-using.
Koch product literature
Detailed product specifications and complete performance data for Koch Permanent Metal Washable Filters (Type MS galvanized steel and Type MA aluminum) are published in Koch Bulletin K985-A: Permanent Metal Washable Filters Product Specification PDF (Koch Filter Corporation).
Commercial & facilities
Buying filters for a building?
Volume pricing on any size or MERV, plus recurring delivery schedules. We handle facilities and commercial orders daily and can usually match or beat distributor pricing.
A filtration company, not a warehouse reseller
Family-founded in 2006, built on the back of 50 years of HVAC filtration experience. Two decades selling filters online — and we only stock what we'd put our own name behind.
Trusted manufacturers only
Every filter we sell comes from a manufacturer we've vetted — AAF Flanders, Koch, NaturalAire, PrimeShield, and a short list of others.
No marketplace-style third-party sellers swapping inventory. No overseas knockoffs relabeled with a domestic-sounding name.
Two decades online
RememberTheFilter.com has been selling HVAC filters online since 2006 — family-founded, founder-operated, and still run by the people who started it.
Schools, clinics, property managers, and homeowners have been ordering from us for years — some of them since before Amazon even sold filters.
Nationwide shipping network
Our distribution network ships from multiple U.S. locations — so most orders arrive faster than coast-to-coast routing would suggest.
Customer service is based in Lake Stevens, Washington — U.S.-based, reachable by phone, text, or email.
Buying this filter for a property, fleet, or facility?
Schools, clinics, property management, multifamily, and government facilities order from us in standing rotation. Volume pricing, tax-exempt setup, and scheduled delivery available.
What customers say about Koch Permanent Aluminum Washable Filter (Type MA, Air or Grease Applications)
Answers to the questions we get every day
From sizing and MERV ratings to bulk orders and subscriptions — here's what customers ask before they buy. For product-specific specs, check the description above.
Not sure if Koch Permanent Aluminum Washable Filter (Type MA, Air or Grease Applications) is right for your system?
Call, text, or email our team. We've been sizing and spec'ing filters for homes and facilities for twenty years.
