How Impact-Resistant Windows Are Rated

When it comes to protecting homes from the ravages of extreme weather, hurricane windows in Pinellas County, FL, are an essential investment. At Clearwater Window & Door Inc., we understand the importance of having robust, reliable windows that can withstand the forces of nature while also offering energy efficiency and security. This guide will delve into how these windows are rated, helping you make informed decisions for your home.

Understanding Impact-Resistant Windows

Impact-resistant windows are designed to endure high winds and flying debris typically associated with hurricanes. These windows are made with laminated glass, which consists of two or more panes of glass bonded together with a clear, strong interlayer. This construction ensures that even if the glass is broken, it remains adhered to the interlayer, preventing dangerous shards from flying into your home.

hurricane windows in Pinellas County FLThe Rating System

Impact-resistant windows are rated based on several stringent tests that simulate the conditions they will face during a hurricane. Here are the key components of the rating system:

  1. Design Pressure (DP) Rating

    This measures the window’s ability to withstand wind pressure. The DP rating is determined through a series of tests that subject the window to various pressures. A higher DP rating indicates a stronger window. For areas prone to severe hurricanes, a DP rating of 50 or above is recommended.

  2. Large Missile Impact Test

    This test assesses the window’s ability to resist impact from large debris, such as a 2×4 wood stud traveling at 34 mph. The test involves shooting the stud at the window in multiple places to ensure the glass and frame can withstand the impact without breaching.

  3. Small Missile Impact Test

    This evaluates the window’s resistance to smaller debris, like roof gravel or small branches, hurled at high speeds. The test uses smaller projectiles shot at the window to determine its durability against minor impacts.

  4. Cyclic Wind Pressure Test

    After impact tests, the windows undergo cyclic wind pressure testing. This involves exposing the window to repeated wind pressures to simulate the fluctuating forces during a hurricane. The window must withstand thousands of cycles without failing.

Standards and Certifications

To ensure the highest quality and performance, impact-resistant windows must meet specific standards and obtain certifications from recognized organizations. The most important standards include:

  • ASTM International Standards

    ASTM E1886 and ASTM E1996 are the primary standards for impact-resistant windows. These standards outline the test procedures and performance criteria for both large and small missile impacts.

  • Miami-Dade County Protocols

    Miami-Dade County in Florida has some of the strictest building codes due to the high risk of hurricanes. Windows that meet the Miami-Dade protocols are considered among the best for hurricane protection. These protocols include rigorous testing for both impact resistance and pressure cycling.

  • Florida Building Code (FBC)

    The FBC sets statewide standards for building construction, including requirements for impact-resistant windows in hurricane-prone areas. Windows that comply with the FBC provide reliable protection and meet the state’s safety standards.

Benefits of Impact-Resistant Windows

Investing in impact-resistant windows offers several significant advantages:

  • Safety and Protection

    The primary benefit is the enhanced protection against hurricane-force winds and flying debris, keeping your home and family safe.

  • Energy Efficiency

    Many impact-resistant windows are also energy-efficient, helping reduce heating and cooling costs. They often feature low-emissivity (Low-E) coatings that reflect heat and UV rays, maintaining a comfortable indoor temperature.

  • Noise Reduction

    The laminated glass in impact-resistant windows also helps reduce outside noise, creating a quieter indoor environment.

  • Security

    These windows provide added security against break-ins, as the tough, laminated glass is challenging to penetrate, deterring potential intruders.

Choosing the Right Impact-Resistant Windows

When selecting impact-resistant windows, it’s crucial to consider the following factors to ensure you get the best protection and value:

  • Certified Products

    Always choose windows that are certified to meet or exceed the relevant standards and codes, such as ASTM, Miami-Dade, and FBC.

  • Professional Installation

    Proper installation is essential for the windows to perform as expected. Ensure that the installation is done by experienced professionals who follow the manufacturer’s guidelines and local building codes.

  • Warranty and Support

    Look for windows that come with a comprehensive warranty and reliable customer support. This ensures you can get assistance and replacement if any issues arise.

  • Material and Style Options

    Consider the different materials (vinyl, aluminum, fiberglass, wood) and styles (single hung, double hung, casement) to match your home’s aesthetics and functional needs.

We specialize in providing high-quality, impact-resistant windows that are designed to meet the rigorous demands of hurricane protection. Our windows are not only compliant with all city and state codes but also offer exceptional energy efficiency and security features. With over 60 years of experience, we take pride in delivering superior products and unmatched customer service.


Choosing the right impact-resistant windows is crucial for protecting your home from hurricanes and enhancing its overall safety, energy efficiency, and value. By understanding how these windows are rated and what to look for, you can make informed decisions and invest in products that offer lasting peace of mind.

For more information about our range of impact-resistant windows and to schedule a consultation, visit our website or call us today. Our team is ready to help you secure your home with the best hurricane windows in Pinellas County, FL.

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