Who doesn’t love having big, beautiful windows that provide a clear, unobstructed view of the outside? Well, probably the person who has large glass panes in a hurricane that get pelted with copious amounts of wind-borne debris!
Large window glass panes do look beautiful, but they have a few key issues that may make them a liability for homeowners throughout Florida.
Let’s go over some of the challenges of owning bigger windows, why they can be more susceptible to damage in a major hurricane, and what you can do to reduce your risk.
Why Large Glass Panes in a Hurricane Can Be a Liability
So, what’s the problem with having especially big windows when a hurricane blows through town? The thing is that, the larger the window is, the more strain it will experience from wind pressure, the more likely it is to suffer an impact from flying debris, and the more likely it is to break when exposed to a sudden, heavy impact.
Let’s do some math to help quantify things:
Let’s say your home is facing a Cat 3 hurricane (an alarmingly common occurrence here in Florida over the last decade). As noted by the FSU Florida Climate Center, a Cat 3 storm on the Saffir-Simpson scale has winds of at least 111 mph.
If we plug that figure into a wind load calculator, a 4 sq. ft. window would be subjected to about 126.04 pounds of force while a 16 sq. ft. window would be subjected to 504.1 pounds of force.
Bring that up to a Category 5 storm with 156+ mph winds, and the pressure exerted on those windows jumps to 248.94 lbf and 995.8 lbf of force for the 4 sq. ft. and the 16 sq. ft. windows, respectively.
To put that into perspective, that would be like having a fully-grown adult male standing on your 4 ft2 window or having a grizzly bear standing on your 16 ft2 window.
Another issue with larger window panes is that while they’re experiencing greater wind loads than smaller ones, they’re also subject to heavier flexing when pressed on by hurricane-force winds compared to smaller windows. As glass is not meant to bend, that increases the risk of the window breaking.
Finally, an increase in window size means an increase in the chances of that window taking hits from wind borne debris (WBD).
To go back to the 4 ft2 window and the 16 ft2 windows, the first window is only 25% as likely to take a direct hit as the larger window when both are on the same wall in a storm. And, when it does take an impact, it’s more likely to be nearer the edge of the window pane or on the frame, since the frame takes up a larger overall portion of the window’s area.
Smaller windows are, simply put, less likely to take a hit and experience less stress from high-speed winds. This makes them much safer during a major storm.
The Difficulty of Sourcing Large Glass Panes
One of the biggest turn-offs of overly large windows for homeowners hits before the window ever gets installed: the difficulty and expense of getting the window in the first place.
Many manufacturers have hard limits on the size of the windows they can make. And, above certain sizes, some window types are extremely rare. Because of this, the manufacturer may not be able to make that window as readily as they could make two smaller windows at about half the size the bigger one would have been.
Additionally, transporting the large glass panes for installation can be more difficult. Larger transports with more rigorous protection.
These issues can raise the cost of the window for the buyer (you) significantly.
If you live in a wind borne debris region, there’s another problem with getting large windows… It’s often difficult to find impact-rated windows larger than 72” (6’) tall and 96” (8’) wide. That’s a 48 ft2 window, which is huge.
Bigger windows have a harder time passing impact resistance tests, which means that manufacturers have to take extra precautions and put the larger windows through more tests. These are added costs that they’ll pass on to buyers… often in the form of an exponential price increase.
The Solution to the Problem of Large Glass Panes in a Hurricane: Mullions
One of the ways that you can make filling particularly large window openings in your home more affordable is to have your window installer use mullions (sometimes called mull bars) to break big window openings into several smaller ones.
Going from one 48 ft2 window to four windows that are each just under 12 square feet can make them much easier for the manufacturer to produce and transport, which helps reduce your costs. It also allows each window frame to have a higher individual DP rating, making it easier to pass Florida Building Code requirements (Larger windows typically have lower DP ratings than smaller ones with the same construction and materials).
Adding mullions and splitting up one big window installation job into a few smaller, easier-to-perform ones can be a great way to save money and add some visual flair to a bigger window opening.
And, for operable windows that you can open and close, it can even help you get finer control over air flow in a room. If it’s a nice day out and you want to enjoy the breeze without letting in too much air, you could open just a single window out of the bunch.
Need Impact Windows for Hurricane Season?
Reach out to Karoly Windows & Doors today for a free in-person window installation consultation! Our experts can walk you through your impact window options and needs, explain how mullions work, and provide you with a breadth of hard-earned industry knowledge.
And, if you choose to use Karoly Windows for your windows with large glass panes in a hurricane, you can rest easy knowing that you’re getting expert installation from one of the highest-rated specialty teams in Tampa Bay!
We’re so confident that the windows we install will be perfect that we back up every installation with a 25 year labor warranty and a 50 year material warranty. Reach out today to get started!
