Energy-efficient windows for North Texas homes

ENERGY STAR targets for DFW counties

ENERGY STAR splits the country into four climate zones and sets window targets for each. The Metroplex straddles two of them, so the right glass depends on your county.

Lower numbers are better for both. Some cities, like Carrollton, Frisco and Richardson, cross county lines; there we recommend glass that meets the stricter South-Central target so you're covered either way. Source: ENERGY STAR climate zones by county and Version 7.0 window criteria.

How to read a window label

Every rated window carries a label from the National Fenestration Rating Council (NFRC). These are the numbers on it, and what they mean for a Texas home.

U-factor

How well the whole window keeps heat from passing through it. Lower is better. It matters most on cold nights and the hottest afternoons, when the gap between indoor and outdoor temperatures is widest.

Solar heat gain coefficient (SHGC)

The share of the sun's heat that gets through, from 0 to 1. In a cooling-dominated climate like ours, this is the number that most affects summer comfort and your electric bill. Look for 0.23 or lower.

Visible transmittance (VT)

How much daylight comes through. Higher means brighter rooms. Good Low-E glass keeps VT high while keeping SHGC low.

Air leakage

How much air seeps through the window itself. Lower is better; it's one reason tight- sealing styles like casement and picture windows perform so well.

Low-E glass: the biggest upgrade for Texas heat

Low-E (low-emissivity) glass has a microscopically thin metallic coating that reflects infrared heat while letting visible light through. In summer it keeps the sun's heat outside; it also filters most of the UV light that fades floors, rugs and furniture.

Coatings are tuned for different climates. For North Texas, choose a coating designed for a low SHGC rather than one built to capture winter sun.

Panes, gas fill and spacers

Double-pane windows seal two layers of glass around an insulating space, often filled with argon gas, which slows heat transfer better than air. Warm-edge spacers around the edge of the glass reduce heat loss and condensation at the perimeter.

When that seal fails, moisture gets between the panes and the glass fogs. Foggy glass can't be wiped clean, and it's one of the clearest signs it's time for replacement windows.

Triple-pane glass adds a third layer. It helps most in cold northern climates; here, a low-SHGC double-pane window usually delivers more comfort for the money.

Vinyl vs aluminum frames

Aluminum conducts heat quickly, so aluminum frames get hot to the touch in summer and sweat in winter. Many 1960s–90s homes across Garland, Richardson, Mesquite and Arlington still have them. Vinyl frames insulate far better, never need paint and hold up well to North Texas sun.

Which windows to replace first

If you're replacing in phases, start where the sun does the most damage:

• West-facing windows, which take the strongest afternoon sun.
• South-facing windows, which get sun for much of the day.
• Large picture windows and bays, where there's simply more glass.
• Upstairs rooms, which already run hotter than the rest of the house.

Why installation matters as much as the window

A top-rated window still leaks if the gap around it isn't sealed. A good installation fills that gap with insulation, seals the frame to the opening and flashes it so water drains away. That's why we measure every opening and install with our own experienced crew, and why the installation method belongs on any quote.