Energy-Efficient Impact Windows in South Florida

What Low-E Glass Changes Day to Day

The difference shows up first on the west and south sides of the house. Afternoon sun through uncoated glass turns the room behind it into the warmest room you own, and the air conditioning answers by running longer to pull that room back down. Lowering the SHGC on that glass reduces how much heat arrives in the first place, so the system has less to remove. We will not put a percentage on your power bill, because the honest answer depends on the glass you have now, how the house is shaded, how well it is insulated, and the age of the equipment. What the rating does tell you is how much solar heat the glass is built to stop.

Two other effects come from the interlayer rather than the coating. Laminated glass absorbs most of the ultraviolet light in sunlight, the part responsible for fading hardwood, rugs, artwork, and upholstery near a sunny window. It also damps sound, because the plastic layer interrupts vibration that would otherwise travel straight through a single pane, so less traffic and aircraft noise comes through. Neither effect shows up on a utility statement, and neither is the reason to buy the window. They come with laminated glass in the opening, and they are worth knowing if you are deciding which elevations to do first.

Specifying Energy-Efficient Impact Windows Opening by Opening

There is more than one way to lower solar heat gain, and the options trade against each other. Tinted glass works by darkening, which cuts heat and daylight together, so the room gets cooler and dimmer at once. A spectrally selective Low-E coating is designed to separate the two, holding back infrared energy while passing more of the visible light, which is how a coated clear unit can carry a low SHGC and still keep a reasonably high visible transmittance. Which one belongs on an opening depends on what the room is for. A dim kitchen is a poor trade. A west-facing bedroom that bakes at four in the afternoon is a different calculation.

The second decision is whether the unit is a single laminated lite or an insulating unit with a second pane and a sealed air space. Most impact glass in South Florida is laminated monolithic, and it does well here because SHGC is carrying the load. A second lite mainly improves U-factor, which counts for more in heating climates, though it can add a measure of sound control as well. Insulating impact units also weigh more and cost more, so they are worth specifying where there is a reason rather than across a whole house. Our showroom at 5908 Johnson Street in Hollywood is the easiest place to see the options in person before anything is ordered.

Related Impact Window and Door Services

The glass is only half the picture when you are specifying energy efficient impact windows, because the window style affects how well the opening seals. A casement or awning window pulls tight against its frame when you crank it shut, which is part of why those styles tend to post low air leakage figures. Sliding and single hung windows seal along a track or a meeting rail instead, a different mechanism with a different result. If you are already choosing styles, look at the energy numbers and the operation together rather than settling the look first and accepting whatever glass comes with it.

Explore the window styles, impact doors, and financing options we offer.

Product Approval, the Energy Code, and Your Permit

In Broward and Miami-Dade, energy efficient impact windows have to satisfy two separate reviews, and homeowners usually only hear about one. The structural side is covered by a Miami-Dade County Notice of Acceptance (NOA) or a Florida Product Approval, which records that a specific window, in specific sizes, with specific glass, passed the High-Velocity Hurricane Zone test protocols. The energy side is covered by the energy conservation provisions of the Florida Building Code, which set limits on how fenestration may perform. Both are checked against the product documentation at permit, so before you sign, compare the glass named on the approval with the glass named on your contract. If the two do not match, ask why.

As an authorized PGT dealer, including the former CGI lines, and a certified general and glazing contractor, America's Window & Door specifies the window, pulls the permit, submits the product approval, and installs the unit so it performs to both of its ratings. We also carry ECO Window Systems, ES Windows and ESR Impact System. Installation matters more to the energy side than most people expect. Air leakage is one of the ratings on that label, and a window that sits out of square, gets shimmed unevenly, or is sealed poorly at the perimeter will leak air no matter what the glass was rated to do. Careful anchoring, flashing, and perimeter sealing are what let a window deliver in your wall what it delivered in the test lab.