April showers bring May flowers, but storms are not welcome. These are crazy times. I woke up this morning to the sound of thunder. Then I heard the wind and rain. It was buckets of rain as if a giant bucket of water was being poured over my house. ‘I hope the skylight doesn’t start leaking again,’ I thought. Then I came downstairs to look out the patio door and saw wind whipping water against the door and windows. This led me to ponder … how well would my windows fare in the event of a violent storm?

The majority of consumers in non-coastal areas usually focus primarily on thermal performance ratings when comparing window performance for a possible purchase. This is primarily due to the existence of the National Fenestration Rating Council (NFRC) labeling, the Energy Star program, and the degree of consumer education that has been undertaken in the door and window industry surrounding thermal performance. U-value, solar heat gain coefficient (SHGC), visible transmittance and air infiltration ratings are listed on the label and are often talked about and compared in the literature, on manufacturers’ websites and in discussions with the sales staff. However, outside of coastal areas, the structural ratings of windows are not as often discussed, if at all.

However, with the frequency and severity of inland storm systems that we have been hearing about in the news, the structural design performance (DP) ratings of windows could definitely be of interest to potential buyers in non-coastal areas as well.

I checked out the websites of some window fabricators to see what they say about the structural ratings of their doors and windows. I was particularly impressed with the information provided by Sun Windows & Doors in Owensboro, Kentucky. When a prospective customer checks out Sun’s website, he or she can click on the technical tab and see the design pressure ratings for every type of window that Sun makes, including various sizes. For example, here are DP ratings for Sun’s vinyl double-hung windows. This plethora of useful information explains why Sun Windows is often chosen by architects when designing some really prestigious commercial developments.

But notice on the Sun page that these are “PG” ratings. The industry started out with DP ratings years ago, so why are we now talking PG ratings? How confusing! What’s the difference anyway? Well, the two ratings are almost the same, like maybe two thirds the same, at least. I like the explanation given by Lyndale Glass entitled, “What is a DP Rating? Is it like a PG Rating?” Check it out. It explains how we got here.

Yes, so even architects can get confused over what these structural ratings actually mean. So, this is why Brent Magnum, corporate training director and architectural consultant for AMSCO Windows, has been training architects on the importance of understanding these structural ratings and choosing the correct window system based upon both the proper design criteria for the building involved while keeping within budget constraints. This interview with Brent published in Reflexion Magazine is a perfect explanation of the differences between DP and PG ratings and is very helpful in explaining the criteria that architects should be considering when it comes to choosing the proper windows whether it be for a family dwelling, a low-rise building, mid-rise or even a high-rise project.

But what about homeowners? Is this all too confusing for ordinary homeowners to grasp and understand? I think it boils down to education. Just as Brent has been working on educating architects, door and window companies should seek to educate and inform all potential consumers, even residential prospects, regarding the structural ratings of the various door and window products they are marketing.

I really feel that structural ratings are the next frontier in educating prospective consumers when it comes to choosing the best doors and windows under consideration.

After all, you don’t want your windows to be “gone with the wind!”

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