Are there Different Grades of Impact Windows?

design pressure or performance-grade impact windows

Yes, there are different grades of impact windows for your home or business. So, you might be wondering what impact windows are and how they differ from regular windows. In this blog post, we will explain what impact windows are, how they work and are graded, and the factors that affect their costs.

What are Impact Windows?


High-rated impact windows near St Petersburg, FL, are designed to resist the penetration of flying debris during a storm, protecting a home or commercial structure from wind infiltration and resulting damages. Once a structure is compromised and penetrated by flying debris, internal pressure builds up, leading to severe structural damage.


Impact windows differ from regular windows by incorporating reinforced frames and laminated glass for added protection. Laminated glass is made of two or more layers of glass bonded with a more tearing-resistant transparent plastic laminate layer. Laminated glass can also reduce noise, UV rays, and heat transfer, making it more energy-efficient than regular glass.


How do Impact Windows Work, Tested, and Rated?

top different impact windows grades to prevent storm damage


Impact windows work by absorbing and dispersing the energy of an impact rather than shattering or breaking. When an object hits an impact window, the outer layer of glass may crack, but the inner layer of laminate will hold the glass together and prevent it from flying into the building. The frame of the window will also resist bending or breaking under pressure.


Impact windows are tested and certified according to various standards and ratings that measure their performance against air, water, and structural loads. The higher the rating, the better the performance. Some of the standard ratings for impact windows are:



  • Performance Grade (PG): A rating that confirms a window has been tested against air, water, and structural standards. The higher the PG rating, the better the performance. Today, the impact window performance rating is more reliable than the design pressure rating, so ask the expert about it.


  • Large Missile Impact (LMI): A test that simulates an impact from a large object, such as a 9-pound 2×4 lumber missile traveling at 50 feet per second.


  • Small Missile Impact (SMI): A test that simulates an impact from small objects, such as gravel or roof tiles, traveling at 80 feet per second.


  • High-Velocity Hurricane Zone (HVHZ): A designation for areas that are prone to extreme wind speeds and require the highest level of protection.


Factors that Affect Impact Window Costs


There are different types and grades of impact windows available in the market, depending on your needs, budget, and location. Some of the factors that affect the type and grade of impact windows are:


  • Window style: There are various window styles, such as casement, awning, double-hung, single-hung, sliding, picture, bay, bow, etc. Each style has advantages and disadvantages regarding functionality, aesthetics, and performance.


  • Window material: Different materials for window frames and sashes, such as vinyl, aluminum, wood, fiberglass, etc. Each material has pros and cons regarding durability, maintenance, cost, and energy efficiency.


  • Window brand: Different window brands offer impact windows with varying levels of quality, warranty, service, and reputation. Some of the popular impact window brands include Andersen®, Simonton®, PGT®, CGI®, etc.


  • Window options: Different options, such as low-emissivity coatings, argon gas fillings, tinted glass, decorative grids, custom colors, etc., can enhance the performance and appearance of your impact windows. Each option has its benefits and drawbacks regarding functionality, cost, and aesthetics.


The Conclusion: Different Grades of Impact Windows


To choose the right type and grade of impact windows for your home or business, consult a professional window installer in Clearwater to help you determine your local code requirements. 

They will measure your window openings accurately, provide you with a free quote, and install your new impact windows properly. Consider comparing different window brands, models, ratings, options, and prices to find the best value for your money.

Impact windows are an excellent investment for anyone who lives in a coastal area that experiences extreme weather conditions. They can protect your property from wind damage, reduce energy bills, increase your comfort, enhance your security, improve your curb appeal, and add value to your home.

However, not all impact windows are created equal. Do your research and consult with a professional before buying or installing any impact windows for your home or business.

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