If you want to maximize your home’s wind mitigation so you don’t have to worry about hurricanes, impact windows are the way to go. But, which impact windows are the best windows for hurricanes?
There are many things to consider when choosing a window for hurricane resistance. Not only should you consider the maximum design pressure rating of the window, but its water resistance, seal quality, u-factor rating, solar heat gain coefficient (SHGC), operation style, and overall look.
After all, the best windows for hurricanes will still need to be viable for the rest of the year when your home isn’t beset by the worst weather conditions Florida can bring!
Let’s go over what makes for the best windows to handle the hassles of hurricane season (and beyond):
What Makes for the Best Windows for Hurricanes: Design Pressure Rating
While design pressure isn’t the only factor to consider when choosing a window, it is an important one. So important that it’s typically the first thing to look at. After all, if a window doesn’t have sufficient durability to withstand extreme wind pressure, then it won’t protect your home effectively when it matters most.
Design pressure, or DP, is measured as both a positive and a negative number on a window’s specification sheet or NFRC label that tells you how much wind force the window can withstand. The higher the number, the more wind it can take. The positive number indicates how much inward-acting pressure the window can withstand while the negative number tells you how much outward-acting pressure it can take.
This is expressed as pounds per square foot. So, a window with a DP of +/- 50 would be able to withstand 50 pounds per square foot of pressure.
The DP requirement for windows can vary from one area to another, as local building codes may impose stricter requirements than others based on risk. For example, municipalities in wind borne debris regions (WBDs) tend to require higher DP ratings than ones located more inland.
Also, windows on higher floors of a home may need higher DP ratings than ones on the ground floor, as wind force increases with the height of the building. Why? There are several reasons. One of the bigger ones is surface friction.
As noted by The Weather Prediction, “Surface objects such as trees, rocks, houses, etc. slow the air as it collides into them. The influence of this friction is less with height above the ground.” So, as you get higher off the ground, the fewer obstructions there are to the wind before it hits your home. This means that there’s less to slow the wind down, increasing its velocity when it finally does make impact.
Why Does Design Pressure List Two Numbers?
That’s because homes face both inward and outward-acting pressures during a hurricane. When wind is pressing against one side of a house, the opposite side is pulled by a suction force roughly equal to the pushing force being exerted on the structure.
So, DP ratings have to account for this fact. If a window (somehow) managed to have a DP of +55 and -35, it wouldn’t be considered properly hurricane-resistant in a region where the minimum DP requirement is +/- 40.
What Makes for the Best Windows for Hurricanes: Water Penetration Resistance
If an impact window can stand strong against severe wind, but leaks like a sieve, is it really protecting the inside of your home? No. It isn’t.
So, another important consideration for any impact window you choose is how well it resists water penetration. In most cases, a high design pressure rating corresponds to a high water penetration resistance rating.
However, to verify water penetration resistance, window products are typically assessed using ASTM E331 in laboratory conditions or ASTM E1105 in the field.
Both versions of the test involve spraying water at the window while subjecting it to a specific air pressure differential. The interior face of the window is then inspected for any signs of water leaking through the window. If there is excessive leakage, the window fails the test.
What Makes for the Best Windows for Hurricanes: U-Factor
U-factor is a measure of how well the window insulates your home against exterior temperatures. The smaller the number, the less heat leaks through the window (in either direction).
This is a critical factor for determining a window’s overall energy efficiency, and a hugely important consideration in Florida. For most of the year, Floridians face hot temperatures—especially during hurricane season.
Proper insulation is a key part of keeping your home cool even during the hottest months of the year when you’re exposed to the greatest risk of hurricane formation. This lets you keep your home comfortable without having to rely on the air conditioner. This, in turn, helps you reduce your electricity use so you can save money on your utility bills.
For that reason alone, U-factor should be a consideration when choosing the best windows for your home, hurricane season or no!
What Makes for the Best Windows for Hurricanes: SHGC
Solar heat gain coefficient is a way to measure how much of the sun’s heat gets through your window into your home. It’s a separate statistic from u-factor, which measures how well the window stops ambient heat transfer.
Similar to u-factor, the smaller the number for the SHGC rating, the less of the sun’s heat can get through the window. This means it will take longer for a window with an SHGC of 0.23 to let in as much heat as a window with an SHGC of 1.
Solar Control type low-e glass windows tend to have the best SHGC values. They achieve this by using a thin layer of reflective material that repels infrared and ultraviolet light waves. It’s these light waves that carry the majority of the suns’ heat into the home. However, visible light is still able to get through the window unobstructed.
So, a window can look nearly crystal-clear and still have an excellent SHGC value.
Do Dark Tints Block the Sun’s Heat?
This is a common misconception about windows. There’s the assumption that a dark-tinted window will be better at blocking the heat of the sun than a clear window.
However, a dark tint does not automatically mean that the window is better at stopping the sun’s heat. In fact, it may be worse than an identical window without the dark tint.
This is because dark window tints only block visible light transmission, not infrared or ultraviolet light. This may be somewhat effective for enhancing privacy, but does nothing to stop the heat of the sun from penetrating into your home.
Additionally, as anyone who owns a dark-colored car in Florida knows, darker colors absorb and trap extra heat from the sun. So, a dark window tint may actually make your home warmer than it would be otherwise.
What Makes for the Best Windows for Hurricanes: Window Type
There are many different types of windows that you can choose from for your home. The most common types are:
- Single-Hung Windows. A type of hanging window with one fixed sash and one moving sash. One of the most common types of windows found in new construction throughout Florida because of their relatively low cost.
- Double-Hung Windows. A type of hanging window that looks nearly identical to the single-hung, but both sashes are able to move up and down. This allows you to open the window from the top or the bottom.
- Sliding Windows. A type of window with at least one movable and one fixed sash, though they may have more than this. The movable sash(es) roll left and right on rollers inside of a track similar to a sliding glass door.
- Casement Windows. A type of window that imitates classic swinging windows, only with the use of an armature and crank mechanism to swing open and shut. The armature secures the window in place when open, and it can latch shut tightly. Notable for providing better air circulation for any given window opening due to moving the sash out of the way of the opening.
- Awning Windows. Similar to casements, these windows swing open on an armature, but do so vertically. Useful for maximizing air flow in a room while providing shelter from light rainfall.
- Picture Windows. These are non-opening windows which are, effectively, a clear wall rather than an opening into the home. The lack of moving parts enhances their rigidity and makes installation simpler, but the larger panes of glass tend to demand a higher price (the cost of window glass rises exponentially past a certain point, and picture windows have a single large pane rather than several smaller ones).
Which type of window is the best for facing hurricanes? The answer depends on the window opening and your preferences.
Picture windows are perfect for ensuring 24/7 protection since they never open. Meanwhile, casement windows, especially ones with multi-point locking systems, are incredibly resistant to outward-acting pressure. Sliding windows lock securely and are resistant to being blown in, and hanging windows (both single- and double-hung varieties) are excellent for tall, narrow window openings.
For most though, the best window type to protect your home from hurricanes will be the one you find easiest to use and the most visually appealing.
Get the Best Windows for Hurricanes from a Professional Installer!
Need new impact windows to protect your home from hurricanes and other hazards year-round? There’s one last thing you need to consider: the quality of the installation.
You could buy the best impact windows ever made, and if they aren’t installed correctly, you’ll find that they don’t offer the protection you need when you need it.
That’s why you need to find an installer who does things the right way, every time. One that uses not only top-quality windows, but best-in-class materials like high-grade caulk and composite shims that resist water penetration. One that doesn’t cut corners by hiring subcontractors that may or may not even be qualified to install windows.
Only by combining the best windows for hurricanes with the best installation process can you ensure that your home’s window openings are fully protected against hurricane season. Reach out to Karoly Windows & Doors today to get started with a free in-home consultation!
