Electricity rates in Louisiana keep climbing, and for most homes here, cooling is the single biggest part of that bill. If your windows haven't been replaced in decades, energy-efficient windows are one of the most practical ways to reduce energy use and improve comfort.
Many generic energy-efficient window resources focus on colder climates, where the main concern is keeping heat in. In Louisiana, the problem is cooling. LAS builds windows around that difference by using Cardinal® Low-E glass, a design that exceeds ENERGY STAR® Southern Region requirements, and nearly 70 years of manufacturing experience designing windows that stand up to the Gulf South's heat and humidity.
LAS has been manufacturing and installing windows in the Gulf South since the 1950s. Our windows are built locally, by local installers, for local conditions, and not shipped in from a national supplier. Nearly seven decades in one region teaches you exactly what heat, humidity, and storms do to a window over time. We know windows because we've been building them right here the whole time.
Windows designed for high heat and humidity
Most of what homeowners read about "energy-efficient windows" was written for northern climates, where the goal is keeping heat in. That's a different engineering problem than the one Louisiana and other Gulf South homes face, where the goal is keeping heat out for eight or nine months of the year.
By looking at a window's ENERGY STAR label, you can find out what the window was built for:
- U-Factor measures how much heat flows through the window. A lower U-Factor means better insulation. This is the number that matters most in cold climates, where heating dominates the energy bill.
- Solar Heat Gain Coefficient (SHGC) measures how much solar radiation passes through the glass. A lower SHGC means less heat gets in. This is the number that matters most in the Gulf, where cooling is what runs up your electric bill.
A window can have an excellent U-Factor and still perform poorly in Louisiana if its SHGC is high. That's the gap a lot of energy-efficient windows sold nationally fall into, and it's why LAS designs around SHGC first.
Benefits of Energy-Efficient Windows
Lower energy bills by reducing cooling demand
Better indoor comfort during hot weather
Protection from UV rays that can fade flooring and furniture
Reduced drafts and air leaks around window openings
How Low-E Glass technology works
Sunlight is made of three types of energy: ultraviolet light (which fades fabrics and flooring), visible light (what you see by), and infrared light, which is the long-wavelength energy that's the primary source of heat gain through a window. In a hot climate, infrared light is the main thing working against your air conditioner.
Low-E glass (the "E" stands for emissivity) is coated with microscopically thin layers of metal, typically silver, that reflect infrared energy before it can transfer through the glass. The lower a glass's emissivity, the better it blocks that heat transfer.
There are two ways this coating gets applied, and the difference matters more than most homeowners realize:
- Hard coat / "passive Low-E" is fused to the glass at high heat during manufacturing. It's durable and easy to work with, but it still lets more infrared energy through, which makes it better suited to northern climates focused on heat retention.
- Soft coat / "solar control Low-E" is applied to the glass in a vacuum at room temperature and sealed inside an insulated glass unit. It blocks significantly more infrared and some UV light, which makes it the better-performing option for a cooling-dominated climate like ours.
LAS uses a soft coat glass called Cardinal® LoĒ³-366, which currently offers some of the strongest insulating performance available in clear Low-E glass.
There's also a placement detail most manufacturers don't talk about: in a double-pane insulated unit, the coating can sit on any of four glass surfaces. Manufacturers building for northern markets typically apply it to surface 3 (the inner pane, facing out) because that position is better for retaining indoor heat. LAS applies it to surface 2 — the outer pane, facing inward — because that position is more effective at reflecting solar heat before it ever reaches your glass. It's a small manufacturing decision that reflects a bigger point: we build for cooling, not heating.
Here's how Cardinal® LoĒ³-366 compares to clear glass and to the "ordinary" Low-E glass found in many mass-produced windows. Lower numbers equal better insulating performance.
| Glass Type | U-Value | Solar Heat Gain Coefficient |
|---|---|---|
| Clear Glass | 1.04 | 0.86 |
| Ordinary Low-E | 0.30 | 0.72 |
| Cardinal® LoĒ³-366 (LAS) | 0.24 | 0.27 |
Our ENERGY STAR Certification for the Southern Region standard
ENERGY STAR is a certification program run by the U.S. Environmental Protection Agency to help homeowners identify products that meaningfully reduce energy use.
Because Louisiana's climate is cooling-dominated, the program holds windows sold here to a stricter Southern Region standard than what's required up north: currently 0.32 or lower for U-Factor and 0.23 or lower for SHGC.
LAS has always moved to exceed ENERGY STAR requirements, not just meet them. LAS has held this level of performance for well over a decade. Here's how our standard window styles perform:
| Window Style | U-Value | SHGC |
|---|---|---|
| Single Hung | 0.28 | 0.21 |
| Double Hung | 0.28 | 0.21 |
| Double Slider | 0.28 | 0.21 |
| Casement | 0.26 | 0.19 |
| Fixed/Picture | 0.26 | 0.22 |
For the complete breakdown of ENERGY STAR ratings and regional requirements, see our ENERGY STAR Rating page.
How energy-efficient windows can reduce cooling costs
The specs above can translate directly into savings you can see on your utility bill.
Per ENERGY STAR's 2023 estimates, homeowners in the Southern Zone who replace single-pane windows with ENERGY STAR-certified windows save an average of $563 a year, or about 12% of their whole-home energy bill. Replacing older double-pane windows still saves an average of $373 a year (about 8%).
Your home's actual savings will depend on its size, orientation, and current windows. Call us for a free estimate to learn more.
Built in the Gulf South, for the Gulf South
Glass technology only performs as well as the window it's built into. LAS's energy-efficient windows are part of our WeatherGard II vinyl window line, manufactured locally in our Gulf South facility:
- Virgin vinyl frames with steel reinforcement for strength and structural integrity
- Multi-chambered frame design that reduces heat transfer through the frame itself, not just the glass
- Double-pane construction filled with argon gas, which improves insulation beyond what the glass coating does alone
- Custom-manufactured to each home's measurements within 1/8” for a tighter fit than stock sizing
Energy efficiency doesn’t stop at the glass
Up to 25% of the energy used to heat and cool a home is lost through windows and doors, but glass specs are only part of that equation. How your windows are oriented, and how well they're installed, matter just as much as what they're made of.
Window orientation
Whether you're planning new construction or adding on to your home, orientation is worth thinking through before the work begins. It doesn't cost anything to plan for, and it changes how much your glass has to work against.
A few things worth knowing before your estimate:
- North- and south-facing windows generally perform better in our climate than east- or west-facing ones
- West-facing windows take the hardest afternoon sun; reducing window count there (or adding shading or shutters) helps
- An overhang over south-facing windows blocks high summer sun while still allowing lower-angle light through
We cover this in more depth, including guidance for both new builds and renovations, in our full guide to house orientation and energy conservation. Our estimators can also walk through your home's specific orientation with you.
Installation quality
Even a perfectly rated window can underperform if it's installed poorly. A gap, an unsealed joint, or a rushed fit can undo the SHGC and U-Factor numbers on the label. That's why LAS treats installation as part of our overall product, not an afterthought:
Our lead installers go through the Installation Masters Certification Program. Every window is sealed using the OSI Quad Max Caulking System, a professional-grade sealant built to stand up to the heat and humidity that wears down standard caulk.
Ready to lower your cooling costs?
LAS has been building windows for Gulf South homes since the 1950s, and in all that time, "good enough to pass" has never been the goal.
We keep raising our own bar because the people buying these windows are our neighbors. It's the same reason our glass exceeds Energy Star's Southern Region requirement instead of just meeting the standard.
Get a free, no-obligation estimate for energy-efficient windows built specifically for Louisiana's climate, and see how your windows can perform better in our Gulf South climate.
