The Honest Broker: Hurricane vs Impact Windows

The Honest Broker: Hurricane vs Impact Windows


Hurricane season begins on June 1st and it is important to review the difference in window protection because not all “impact windows are equal.” It is very important for homeowners to understand that although the terms are used interchangeably, this is not the case.

Let’s break down the difference between hurricane impact and impact windows (found on the shelf at home improvement stores). Impact windows are what’s used for car windshields. A shatter-resistant film is applied to the glass to prevent it from completely breaking. This would otherwise send glass fragments flying (which could injure someone) and leave a gaping hole in the space. Instead, the glass may crack if enough pressure is applied, but the glass won’t fly off or leave a gaping hole behind. An impact window is one that will provide safety from flying glass shards.

Hurricane impact windows, on the other hand, are comprised of several layers. Some of these are glass and others are PVB plastic. The plastic layers in between the glass layers work like a glue that holds the glass together, preventing it from shattering, and function as a stronger layer of protection. During a hurricane, debris can get launched at lethal speeds, but the plastic layers will not break when struck by them. Instead, the outer layer of glass may develop a spider crack, but the door or window won’t budge.

Hurricane impact windows may not look much different from traditional windows, but they are different because they are stronger and have been rated as superior when it comes to protecting your home from storms. Typically, hurricane impact windows are made from laminated and tempered glass and set in a reinforced frame, which makes them almost impossible to break. If they are damaged, they will tend to crack in a spiderweb-like fashion, rather than blowing out completely, which means you won’t end up with dangerous shards of glass flying around everywhere injuring people. Hurricane impact windows have also been tested repeatedly and extensively to ensure that they are able to protect properties from extreme winds, water pressure, and other kinds of structural damage, which is something your average window just isn’t able to do.

Hurricane Impact Windows: How Are They Rated?

You might think it would be simpler to manufacture all hurricane impact windows to the same standards, but because all homeowners have different requirements, and different price points to consider, they come in a variety of strengths and ratings so that you can choose the windows that will best meet your needs. With that in mind, here are the most important hurricane impact window ratings and what they mean:

Designs Pressure Rating

The DP rating of impact windows is the most used testing. It uses a number-based system to show the buyer how well a window can withstand water penetration or wind pressure. When coming up with a DP rating, testers must consider at least two of the following: Air infiltration, Water infiltration and Structural load. The higher the DP number, the better the window is at enduring the three above issues.

Wind  Scale Ratings

Hurricanes are rated categories 1-5 depending on the level of sustained wind speed they generate. You will probably know, living in Florida, that a category 1 is the less serious, with speeds of between 74 and 95 mph, while a category 5 is the most severe, reaching speeds of 157 mph or above. Hurricane impact windows that have been wind scale rated will tell you exactly which category of hurricane they are able to withstand.

Solar Heat Gain Coefficient

SHGC ratings can tell you how much solar radiation can pass through your windows and get into your home. The lower the number the better they can do their job.

Thermal Properties

Most hurricane impact windows will also have a thermal rating (or several) which will tell you exactly what they are capable of. These could include any of the following: a.) Light-to-solar gain, b.) Thermal conductivity. c.) Air leakage, d.) Condensation resistance, and many more.

Be Well!


Diane Lott, Broker

Owner: Paradise Found Realty

*The highest compliment you can give is when you feel you can refer a friend…
  Hope to see them soon!

Paradise Found Realty, Inc. of Palm City



Phone:  954-294-5060

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