So, you’re online shopping for new impact windows for your home because you want the best possible windows to protect against storms, intruders, and other hazards. Odds are good that you’ve seen ads for both custom vinyl windows and for aluminum windows.
At first glance, aluminum windows might seem like the way to go for maximum security and impact resistance. In fact, aluminum (and other metal) windows do tend to have the highest design pressures of any impact window type.
It makes sense: aluminum is a very durable material, after all. However, aluminum windows aren’t necessarily the best impact windows for Florida homes.
Custom vinyl windows are the best choice for Florida homes. But before we explain why, let’s take a look at some of the characteristics of each material:
What Are Aluminum’s Characteristics?
First, before we define aluminum’s characteristics, we need to understand which alloy of aluminum we’re discussing. While aluminum is a chemical element (the 13th element), like iron (the 26th element), it’s rarely used in a pure form. Instead, aluminum is typically alloyed with other elements like magnesium, iron, silicon, zinc, etc. to enhance its properties.
A common alloy of aluminum used in architectural trim and window frames is 6063 aluminum, but it’s far from the only alloy a window manufacturer might use. The basic characteristics of 6063 aluminum are:
- Ultimate Tensile Strength: 145 MPa (Megapascals) or 21,030.5 psi (pounds per square inch). This is how much stress a material can take before breaking when it’s stretched or pulled.
- Density: 2.70 g/cm3. How heavy the material is per cubic unit. At 2.7 grams per cubic centimeter, a cubic meter of aluminum would weight 270 grams, or about 0.6 pounds (rounded up from 0.595248 lbs).
- Thermal Conductivity: 201 W/mK (Watts per meter Kelvin). A measure of how efficiently thermal energy passes through the material. The higher the number, the more heat can pass from one end of the material to the other end.
Properties of PVC Used in Custom Vinyl Windows
So, how does the polyvinylchloride (PVC) used in custom vinyl windows stack up against aluminum in terms of performance characteristics? Here are some of the relevant characteristics as noted by Vinidex:
- Ultimate Tensile Strength: 51 MPa/7396.92 psi.
- Density: 1.42-1.48 g/cm3.
- Thermal Conductivity: 0.16 W/mK
To summarize, the direct comparison of these three key performance characteristics are:
| Property | Vinyl | Aluminum | Winner |
| Ultimate Tensile Strength | 51 MPa | 145 MPa | Aluminum by 95 MPa |
| Density | 1.42 g/cm3 | 2.7 g/cm3 | Vinyl by 1.28 g/cm3 |
| Thermal Conductivity | 0.16 W/mK | 201 W/mK | Vinyl by 200.84 W/mK |
So, Why ARE Custom Vinyl Windows Better Than Aluminum Windows in Florida?
When it comes to ultimate tensile strength, aluminum is the clear winner, being almost three times (2.84x) times stronger than vinyl. It can also be deformed without completely failing, where pure, unplasticized vinyl tends to break if bent out of shape.
However, vinyl is 52% the weight of aluminum (already a lightweight material) per cubic meter and it transfers less than 1/100th of 1% of the thermal energy that aluminum does.
To put that into perspective, for every 1,000 watts of energy that aluminum lets into the home, vinyl will only transfer 0.796 watts of energy. It takes 3.6 watts of energy to power a 1,000-watt light bulb for a second.
In other words, the energy let in by the aluminum window frame could power a 1,000 watt light bulb for an hour, while the vinyl window frame would only let in enough to let that light shine for less than a third of a second.
This thermal transfer is the biggest reason why aluminum windows aren’t suitable for impact windows in Florida. For most of the year, the hot Florida sun creates high temperatures… and aluminum efficiently carries that heat straight into your home, even if you use low-e glass for your windows.
Another issue that aluminum has when compared to vinyl is that it corrodes when exposed to salty ocean air. While it can, if cared for and given a strong coating of paint, resist chemical corrosion from salt exposure, the simple fact is that aluminum is much more susceptible to chemical corrosion than PVC is. This can leave you with unsightly pitting and scarring for your windows that leaves your windows looking worse for wear unless you’re really on top of cleaning and fixing every scratch in the paint after every storm.
SInce vinyl frames are molded in the color that they’re in, small scratches from minor impacts or storms don’t show as readily, meaning that they’ll be looking beautiful with less maintenance even if your home is just off the beach. This means you won’t be outside with a bucket of cleaner and a bucket of paint after every storm that hits your home.
Can Custom Vinyl Windows Meet Florida Building Code Impact Standards?
Yes! A custom-made vinyl window can be manufactured to withstand impacts well enough to stand up to even Category 5 hurricane conditions needed for HVHZ areas, let alone the basic wind borne debris (WBD) region resistance mandated by the Florida Building Code (FBC).
But, what about the impact resistance? Aluminum does a great job of withstanding extreme forces—much better than PVC, in fact. Well, that’s why impact-rated custom vinyl window frames have some aluminum buried deep in the core of the window frame.
The aluminum core is covered by several layers of vinyl with air gaps to inhibit thermal bleed so that your window has the strength of a metal-cored window frame without sacrificing its energy efficiency or resistance to corrosion.
This brings up the durability of the window frame to more easily meet the requirements of WBD regions in Florida.
Need Custom Vinyl Windows for Your Home?
If you’re looking for custom vinyl windows to protect your home from hurricanes and other threats, Karoly Windows & Doors is your go-to source! We work with the best impact window brands for the Florida market and back those high-quality windows up with the best installation quality you can get!
What sets us apart from other window installation companies is that we always use in-house installers for every window installation. We don’t farm out installs to third party subcontractors.
This lets us ensure tight quality control for your installation from start to finish, as it’s our installers following our process for every install. What does that mean for your windows? It means that you’re getting consistent quality and results.
With subcontractors, you never know if you’re getting licensed, skilled labor for your impact window installation project. It’s like playing Russian Roulette with your whole home. Many subcontractors are underpaid, overworked, and are treated as disposable by the window companies they work with, leading to them cutting corners on installs to get things done faster and cheaper so they can pocket more money.
Skip the drama, difficulties, and disastrous results by working with a proven window installation company! Reach out to Karoly Windows & Doors today to get started!
