Energy-efficient windows for Florida heat
In Florida, keeping the sun's heat out matters more than keeping heat in. Here is what to look for.
Last reviewed September 27, 2026
The two numbers on the label
Most windows carry a label from the National Fenestration Rating Council (NFRC) with two key ratings:
- Solar Heat Gain Coefficient (SHGC). How much of the sun's heat passes through the glass. Lower is better in Florida.
- U-factor. How well the window keeps heated or cooled air from escaping. Lower is better.
ENERGY STAR sets separate limits for the Southern climate zone, which covers Florida. A window that carries the ENERGY STAR label for the Southern zone meets those limits.
Low-E glass
Low-emissivity coatings reflect heat while letting light through. In Florida, a low-SHGC Low-E coating does most of the work of cutting cooling load through windows.
Impact windows and energy
Impact windows can be energy efficient too. Laminated impact glass can be paired with Low-E coatings, and insulated impact units add an air space between panes. Ask for the NFRC ratings of the exact product being quoted.
Frames
Vinyl frames insulate better than plain aluminum. Aluminum frames with a thermal break close much of the gap and are common in coastal areas.
Frequently asked questions
What SHGC should I look for in Florida?
Lower is better. The simplest check is the ENERGY STAR label for the Southern climate zone, which sets a maximum SHGC and U-factor for Florida.
Do new windows lower my electric bill?
They can reduce cooling load, especially when replacing older single-pane or clear-glass windows. Savings depend on your home, the product and how many windows face the sun.
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