What Is a Window Performance Grade?

Performance Grade, commonly abbreviated PG, is a product-performance designation under the North American Fenestration Standard. According to the Fenestration and Glazing Industry Alliance, a PG designation indicates that the tested product met the applicable design pressure plus the other requirements identified by the standard.

Those requirements address multiple areas, including air leakage, resistance to water penetration, structural loading and applicable operating or durability requirements. PG is therefore broader than a structural-pressure number by itself.

Contractors should still confirm that the documented PG applies to the ordered size, operating type and configuration. A single-hung window, casement window, slider, fixed unit and factory-mulled combination should not automatically be assumed to share one rating.

What Is Design Pressure?

Design Pressure, or DP, relates to the pressure a fenestration product is intended to resist under specified design conditions. It is commonly expressed in pounds per square foot.

DP should not be presented as a complete statement of window quality. Structural resistance is important, but it does not independently tell the contractor how the unit performed during every air, water or operational test.

FGIA explains that Performance Grade and Design Pressure were clarified in modern editions of the North American Fenestration Standard partly because products had sometimes been marketed solely by their DP ratings. A PG designation communicates that the product met the broader group of applicable requirements.

PG and DP Are Related, but They Are Not Interchangeable

Why Contractors Should Avoid Converting DP Directly to Miles per Hour

Homeowners frequently ask, “What wind speed can this window handle?” It is tempting to convert a DP number into a single miles-per-hour claim, but that shortcut can be misleading.

The pressure assigned to an opening depends on more than the regional wind speed. The applicable building code or project design may consider building height, exposure category, topography, risk category, the opening's location on the wall and whether it is near a corner or another higher-pressure zone.

The responsible answer is that the product rating must meet or exceed the design pressure required for that specific opening. The building department, project designer, architect or engineer should establish the required value when the contractor is not authorized to make that determination.

Air Leakage Is a Separate Performance Question

Air testing measures leakage through a specimen under controlled laboratory conditions. Passing the applicable requirement does not mean that absolutely no air can move through the window, and it says nothing by itself about air leaking between the window frame and the rough opening.

Homeowners may describe convection near cold glass, leakage around the installation perimeter and air passing through an operating window as the same “draft.” Contractors should inspect the source before blaming the product or promising that a higher PG number will solve every comfort complaint.

What the Water Test Does—and Does Not—Tell You

Water penetration testing exposes the window specimen to water while applying a specified pressure difference. Passing means the specimen met the applicable requirement under that test method.

It does not certify the surrounding wall. A correctly selected window can still experience water problems if the rough opening, flashing, weather barrier, sill drainage or exterior sealant is detailed incorrectly.

This distinction is especially important with new-construction windows. Product performance and installation performance must work together.

Structural Testing Is Not an Impact Rating

Structural testing evaluates the assembly under positive and negative pressure. FGIA notes that windows and doors are structurally tested at a pressure above the stated design pressure under NAFS procedures.

That test should not be confused with large-missile, small-missile or other impact-resistance testing. A standard Gentek 1900 Series window does not become an impact-rated hurricane product merely because it has a strong PG or DP designation.

For projects requiring impact protection or specific coastal approvals, verify the exact model, size, glazing, reinforcement, anchorage and approval documentation before quoting or ordering.

How the AAMA Gold Label Helps

The AAMA Gold Label Certification Program provides third-party verification for qualifying windows, doors and skylights. FGIA explains that a certified product sample is independently tested and that ongoing manufacturing inspections help confirm continued compliance with the applicable standards.

For a contractor, the label provides valuable evidence that the labeled product is associated with a certified tested design. It is not permission to transfer the rating to a different size, style, glass package or field-built combination.

Preserve labels and supporting paperwork until inspections and project documentation are complete. If certification is required, verify the exact product in the current certified-products directory instead of relying only on a brochure or an old proposal.

Installation Still Determines Field Performance

Laboratory testing evaluates a prepared specimen installed according to the applicable test setup. A field installation introduces the rough opening, fasteners, shims, flashing, sealants, drainage plane and interior air seal.

The FGIA InstallationMasters program provides professional training and certification related to the installation of windows and exterior glass doors. Training can strengthen an installer's understanding, but it does not replace the current manufacturer instructions, approved project details or local code.

Follow the current Gentek instructions for the ordered product and match the attachment schedule to the documented configuration. Adding extra fasteners or sealant without understanding the drainage design is not automatically an improvement.

Sales Tips for Discussing Gentek 1900 Series Performance

1. 1. Ask about the project before discussing a rating. Determine the location, building type, opening sizes, exposure and whether project specifications or special approvals apply.
2. 2. Obtain the performance data for the quoted unit. Match the operating style, size, glass, mull arrangement and high-performance options to current documentation.
3. 3. Separate strength from comfort. PG/DP performance, U-factor, solar heat gain, condensation resistance and sound control are different conversations.
4. 4. Avoid “hurricane-proof” and “leak-proof.” These absolute claims exceed what an ordinary product rating establishes.
5. 5. Document the decision. Keep the quotation, performance chart, approval information and installation instructions with the project records.
6. 6. Request help before ordering. Suburban Wholesale can help contractors organize the information needed for an accurate product quotation.

Popular Homeowner Questions

A Practical Preorder Checklist

• Confirm the authority having jurisdiction and applicable code edition.
• Identify the required performance grade or design pressure.
• Confirm the requirement for every opening or pressure zone.
• Match the Gentek model, style, size and glass configuration.
• Verify mulled combinations rather than assuming component ratings carry over.
• Confirm whether impact resistance or a product approval is required.
• Obtain current performance and installation documents.
• Preserve certification labels and order records.
• Coordinate flashing, fastening, drainage and interior air sealing.

Get Help Specifying Gentek 1900 Series Windows

Suburban Wholesale & Supply works with contractors, remodelers and builders throughout the Quad Cities. The team can help review Gentek window options, organize opening information and prepare a product quotation based on the documented project requirements.

Product ratings, approvals, features and availability can vary by window style, size, glazing and configuration. Always review current manufacturer documentation and applicable project requirements before ordering.