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Many windows manufactured in North America carry one or more labels affixed to the frame or spacer bar that provide standardized information about the product’s energy performance, structural rating, or compliance with industry testing protocols. The National Fenestration Rating Council, commonly known as the NFRC, issues one of the more familiar labels, reporting figures such as U factor, solar heat gain coefficient, visible transmittance, and air leakage, all measured according to standardized test procedures rather than manufacturer estimates. These figures allow products from different manufacturers to be compared on a consistent basis, and many jurisdictions reference NFRC ratings, directly or indirectly, in their adopted energy code requirements for new window installations.
The American Architectural Manufacturers Association, or AAMA, along with the Window and Door Manufacturers Association and Canadian Standards Association, jointly maintain a rating system that classifies windows by performance class and grade based on structural testing for air infiltration, water penetration resistance, and wind load resistance. A label referencing this joint standard, often written as AAMA WDMA CSA 101 I.S.2 A440 followed by a designation code, indicates the window met specific tested performance thresholds for its intended application, such as residential or heavy commercial use. The performance class, commonly designated R for residential, LC for light commercial, C for commercial, or AW for architectural, along with a numeric design pressure rating, together describe the wind load and structural performance the tested unit achieved in a laboratory setting.
For an evaluator working a storm damage claim, these labels serve a practical identification purpose beyond their original energy or performance disclosure function. A legible NFRC or AAMA label, combined with any manufacturer specific model or series information printed nearby, can help confirm what product line is installed at a property, which supports both accurate cost estimating and any matching analysis needed when only some units at a property are damaged. Labels are sometimes removed by homeowners or painters over time, so their absence does not indicate anything about the window’s origin or quality, only that the identifying information must be sourced another way, such as through a spacer bar date code or by contacting the original installer. Manufacturer date codes on a spacer bar are often a short alphanumeric sequence representing the plant, shift, and production date, and while decoding them can require contacting the manufacturer directly, the underlying information can narrow down a product’s age even when no other identifying label survives.
It is worth noting that these certification labels describe performance characteristics as tested when the product was new, and they do not indicate current condition. A window with a high performing original NFRC rating can still show reduced performance from age, seal failure, or physical damage, so the label is a starting point for identification rather than a statement about the unit’s present functional state.
An appraiser reviewing a window claim may reference available certification and performance labels as part of identifying the specific product involved and gathering objective, standardized data relevant to cost estimating. This use of manufacturer and testing organization information supports an independent, evidence based conclusion about the amount of loss, separate from any coverage determination, which remains a matter for the policy and the parties.
This article is general education about how the appraisal process commonly works. It is not legal advice, and specific procedures can vary by state and policy.
Russ Lis is a working property insurance appraiser and umpire based in Minnesota, serving clients nationwide. Contact Appraisal Resolution.