What Contractors Should Know About WDMA Testing Procedures

In the window and door industry, the Window & Door Manufacturers Association (WDMA) plays a crucial role in setting the standards for quality, performance, and safety. Contractors who work with WDMA-certified products need to understand how these products are tested—and why those tests matter. Knowing the ins and outs of WDMA testing procedures helps ensure proper installation, informed product selection, and long-term customer satisfaction.

Here’s what every contractor should know about WDMA testing protocols and how they impact your work on residential or commercial projects.

Understanding the Purpose of WDMA Testing

WDMA tests ensure that windows and doors meet stringent performance benchmarks for structural integrity, air and water infiltration, energy efficiency, forced entry resistance, and more. These tests are designed to simulate real-world conditions, including extreme weather, pressure loads, and operational stresses, to ensure reliability and safety.

By using WDMA Windows and Doors that have passed certified testing, contractors can be confident they’re providing clients with high-performance, code-compliant products.

Key WDMA Testing Categories Contractors Should Know

1. Air Infiltration Testing

This test measures the amount of air that passes through a closed window or door under specific pressure conditions. It helps determine how energy-efficient the product will be in maintaining indoor climate control.

Why it matters: Products with poor air infiltration scores can increase energy costs and reduce indoor comfort.

2. Water Penetration Resistance

Water penetration testing determines how well a window or door resists water infiltration during rain and wind. It simulates wind-driven rain and assesses sealing systems.

Why it matters: Especially critical in rainy or coastal areas, this test ensures the window won’t allow water damage behind walls or under flooring.

3. Structural Performance (Design Pressure)

This evaluates how well a window or door can withstand wind loads without breaking or losing integrity. It simulates the pressure from strong winds and gusts.

Why it matters: In storm-prone or high-wind areas, using products with higher design pressure ratings is crucial for safety and building code compliance.

4. Forced Entry Resistance

WDMA tests how resistant doors and windows are to tampering or break-ins. This involves attempts to pry, lift, or manipulate the window using tools.

Why it matters: Contractors working on residential or commercial security-sensitive properties should select products with strong forced entry resistance ratings.

5. Thermal Performance and Energy Efficiency

Testing focuses on U-factor, solar heat gain coefficient (SHGC), and condensation resistance. It evaluates insulation and heat transfer capabilities.

Why it matters: Contractors must select windows that meet local energy codes and deliver on promises of lower utility bills.

WDMA/NFRC Certification Labels: What Contractors Should Look For

WDMA-certified products often feature labeling in collaboration with the National Fenestration Rating Council (NFRC). These labels include:

• U-Factor (measures insulation)

• SHGC (solar heat gain)

• VT (visible transmittance)

• Air Leakage

• Performance Grade (PG)

Understanding how to read and interpret these labels allows contractors to recommend the right product for the right climate and customer needs.

How Testing Impacts Installation

Improper installation can compromise the performance of even the most rigorously tested product. That’s why contractors must:

• Follow the manufacturer’s installation instructions carefully

• Use appropriate flashing and sealants

• Ensure frames are level and square

• Inspect for operational performance post-installation

Doing so preserves the product’s certified test ratings in the field.

Final Thoughts

For contractors, being familiar with WDMA testing procedures isn’t just about product knowledge—it’s about ensuring every installation lives up to performance expectations. Knowing how these tests affect air sealing, energy efficiency, storm resistance, and security gives you an edge in client trust, code compliance, and construction quality.

Whether you’re working on a residential remodel or a large commercial project, choosing WDMA Windows and Doors that meet certified testing standards—and understanding what those standards mean—can help you deliver better results, fewer callbacks, and longer-lasting satisfaction.