Best U-Factor and SHGC for Windows in Texas
Data updated October 12, 2026.
ENERGY STAR Version 7.0 splits Texas into 3 climate zones: Southern, South-Central, North-Central. The limits for each are in the table below. Check your address with the ENERGY STAR climate zone finder.
| ENERGY STAR zone | U-factor | SHGC |
|---|---|---|
| Southern | 0.32 or lower | 0.23 or lower |
| South-Central | 0.28 or lower | 0.23 or lower |
| North-Central | 0.25 or lower | 0.40 or lower |
Across Texas, in the GlassBase heating and cooling model, replacing a single-pane window with an ENERGY STAR window saves 596 kWh per window per year. Upgrading a double-pane window saves 358 kWh.
What matters most for windows in Texas
In Texas, most of the modeled saving comes from cooling: 479 kWh of cooling load against 117 kWh of heating load per window per year, for a single-pane to ENERGY STAR upgrade. SHGC measures how much solar heat the window lets in. A lower SHGC means less heat for the air conditioner to remove.
Results vary inside the state; see the city table below.
Modeled savings per window per year across Texas
One window of 39 × 59 in (1 × 1.5 m), averaged over eight facing directions. Weather: 71 TMY3 weather stations.
| Upgrade | Heating saved, kWh/yr | Cooling saved, kWh/yr | Total, kWh/yr | Natural gas saved, therms/yr gas furnace |
Heat pump + AC, $/yr | Gas furnace + AC, $/yr |
|---|---|---|---|---|---|---|
| Single-pane → double-pane | 113 | 126 | 239 | 4.6 | 13 | 16 |
| Single-pane → ENERGY STAR (each location's zone) | 117 | 479 | 596 | 4.7 | 35 | 39 |
| Double-pane → ENERGY STAR (each location's zone) | 5 | 353 | 358 | 0.2 | 22 | 22 |
Dollar figures use Texas average prices, not your utility's rate. Electricity $0.1547/kWh: Texas residential average, 2025. Source: U.S. EIA, Electric Power Monthly, Table 5.6.B, residential sector, year-to-date through December 2025, retrieved 2026-10-06. Natural gas $1.91/therm: Texas residential average, 2025. Source: U.S. EIA, Natural Gas Prices: price delivered to residential consumers, and heat content of natural gas delivered to consumers, 2025, retrieved 2026-10-06. Heat pump COP 3.2, air conditioner COP 2.5, gas furnace efficiency 85%.
The single-pane and double-pane windows use values from the calculator's reference-window table. In Texas, each location uses the limits of its own ENERGY STAR zone (Southern, South-Central, North-Central). kWh here measures heat, not electricity on a bill. Air leakage and the rest of the house are not modeled. Model version tmy3-hourly-iso13790/f4822a26309b, data run October 12, 2026. How the model works.
Cities in Texas
Modeled savings per window per year in Texas cities with a GlassBase page.
| City | ENERGY STAR zone | Total, kWh/yr single-pane → ENERGY STAR | Total, kWh/yr double-pane → ENERGY STAR |
|---|---|---|---|
| Houston | Southern | 555 | 358 |
| San Antonio | Southern | 634 | 398 |
| Dallas | Southern | 619 | 347 |
| Austin | Southern | 577 | 359 |
| Fort Worth | Southern | 573 | 312 |
| El Paso | South-Central | 584 | 343 |
| Spring | Southern | 569 | 359 |
| Arlington | Southern | 600 | 338 |
| Corpus Christi | Southern | 580 | 392 |
| Plano | South-Central | 619 | 331 |
| Lubbock | South-Central | 603 | 310 |
| Irving | Southern | 619 | 356 |
| Garland | Southern | 612 | 327 |
| Amarillo | North-Central | 544 | 233 |
| Mckinney | South-Central | 619 | 331 |
| Frisco | South-Central | 619 | 331 |
| Conroe | Southern | 567 | 358 |
| Grand Prairie | Southern | 598 | 347 |
| Sugar Land | Southern | 537 | 355 |
| Waco | Southern | 593 | 340 |
| New Braunfels | Southern | 656 | 405 |
| Abilene | South-Central | 701 | 399 |
| Carrollton | South-Central | 612 | 325 |
| Longview | South-Central | 579 | 339 |
| Bryan | Southern | 516 | 310 |
| Wichita Falls | South-Central | 643 | 355 |
| Cedar Park | Southern | 582 | 358 |
| San Marcos | Southern | 656 | 405 |
| Mansfield | Southern | 593 | 345 |
| Galveston | Southern | 500 | 322 |
| Sherman | South-Central | 619 | 331 |
| Coppell | Southern | 612 | 354 |
| Stafford | Southern | 537 | 355 |
| Haltom City | Southern | 581 | 304 |
Payback of each upgrade in Texas
Calculate savings for your ZIP code
Compare states: window energy savings by state.
Frequently asked questions
Which ENERGY STAR climate zone is my home in?
Texas has 3 zones: Southern, South-Central, North-Central. ENERGY STAR assigns them by county, and in some places by ZIP code. The ENERGY STAR climate zone finder gives the zone for an address.
How much can new windows save in Texas?
Across Texas, for a single-pane to ENERGY STAR upgrade, the GlassBase heating and cooling model saves 596 kWh per window per year. At Texas's 2025 average prices from the U.S. Energy Information Administration (EIA), the single-pane to ENERGY STAR upgrade is worth about $35 per window per year with a heat pump. Results differ from place to place; use the calculator for your ZIP code.
Is the ENERGY STAR zone the same as the building code climate zone?
No. ENERGY STAR uses four zones of its own, assigned by state and county. Building energy codes use the IECC climate zones, a separate map with its own window requirements. A window can meet one and not the other, so check both if your project needs a permit.