--- title: "Energy-Efficient Windows for Texas: SHGC, U-Factor, Codes" description: "Pick energy-efficient windows for Dallas and Fort Worth: SHGC, U-factor, Low-E glass, NFRC labels, ENERGY STAR zones, city codes and the ended federal credit." url: https://honeyrock.multisites.ai/energy-efficient-windows-texas publisher: Honey Rock Window and Door phone: +1-214-484-9982 quote: https://honeyrock.multisites.ai/contact-us --- # Energy-efficient windows for Texas homes In Texas, the number that matters most is solar heat gain (SHGC), because summer sun drives cooling costs. Then check U-factor, visible transmittance and the NFRC label. Dallas and Tarrant counties sit in ENERGY STAR's Southern zone. Local energy codes differ by city, so confirm yours. Updated November 5, 20269 min read ![A modern home with large windows lit warm at dusk](https://honeyrock.multisites.ai/_astro/dusk-modern-home-glazing-01.BqSa_uSH_ZVAdNj.avif) ## SHGC leads in Texas Solar heat gain coefficient measures heat from sunlight. A lower number blocks more of it. ## Read the NFRC label The label lists U-factor, SHGC and visible transmittance for the whole window, not just the glass. ## Codes differ by city As of November 2026, Dallas and Southlake cite the 2021 IECC, Highland Park and Frisco the 2024 IECC, and Fort Worth the 2015 codes. ## Federal credit ended The IRS says the window credit covered improvements made through December 31, 2025. ## What makes a window energy efficient in Texas? Three numbers decide it: U-factor, solar heat gain coefficient (SHGC) and visible transmittance (VT). In North Texas, SHGC comes first, because summer sun does most of the damage. The U.S. Department of Energy says efficiency is “primarily a function of the U-factor (thermal transmittance) and solar heat gain coefficient (SHGC).” DOE also says energy savings differ by climate. A window that works well in Minnesota can underperform in Dallas. Choose for your sun, your frame and your code. Then confirm the numbers on the label, not on a brochure. ## What do U-factor, SHGC and visible transmittance mean? U-factor measures heat flow through the window. SHGC measures how much of the sun’s heat gets in. Visible transmittance measures how much daylight gets in. Lower is better for the first two. Higher means brighter rooms for the third. Rating What it measures Direction for Texas Plain note [U-factor](https://honeyrock.multisites.ai/glossary/u-factor) Heat flow through the whole window Lower is better DOE: “the lower a U-factor, the less heat will flow through the window” [SHGC](https://honeyrock.multisites.ai/glossary/shgc) Share of solar heat that gets in, 0 to 1 Lower is better DOE: low gain products (under 0.4) are made for hot climates [Visible transmittance](https://honeyrock.multisites.ai/glossary/visible-transmittance) Share of daylight that gets in, 0 to 1 Higher is brighter DOE: values below 0.5 “noticeably reduce the amount of light” The trade-off is real. DOE warns that tinting can reduce solar heat gain, but it “also reduces the ability to see clearly through a glazing unit.” Ask for a low SHGC and a VT that still feels bright. Read the full explanation in [SHGC and U-factor for Texas](https://honeyrock.multisites.ai/guides/shgc-and-u-factor-for-texas). ## How hot is Dallas-Fort Worth, and why does it change the glass? DFW summers are long and hot, so cooling load drives the choice. The National Weather Service reports that at DFW Airport the average date of the first 100°F day is July 1 and the average date of the last is August 27. The most 100°F days in a year was 71, in 2011. Degree days show the same pattern. A degree day measures how much heating or cooling a place needs. The NWS 1991 to 2020 normals list 2,825 cooling degree days a year at DFW, against 2,218 heating degree days. July and August each log more than 640 cooling degree days. Those are the months your windows work hardest. That is why a Texas spec reads differently from a northern one. You want to block summer sun on east and west faces, and you still want daylight. Values for Love Field, Fort Worth Meacham and other stations are not covered here, because the NWS pages cited use DFW Airport. ## What does Low-E glass do, and what about argon and spacers? Low-E glass carries a thin coating that reflects heat. Argon fill slows heat flow between the panes. A warm-edge spacer keeps the glass edge warmer. Together they improve a window’s ratings, and they are standard on most good insulated units. DOE says “windows with low-e coatings, especially spectrally selective coatings, are effective at reducing summer heat gain and air conditioning costs without significantly impacting visible light or color.” Read more about [Low-E coating](https://honeyrock.multisites.ai/glossary/low-e-coating), [argon gas fill](https://honeyrock.multisites.ai/glossary/argon-gas-fill) and [warm-edge spacers](https://honeyrock.multisites.ai/glossary/warm-edge-spacer). The partner makers describe their glass this way: - **Sun Windows.** All Sun products use dual-glazed insulated glass as standard. Sun says argon “improves thermal performance by slowing convection currents” and that its Duralite spacer gives “a warmer edge-of-glass temperature.” Its Sun Advantage 270 Low-E² glass, per Sun, blocks 63% of the sun’s heat in summer, and the 366 is a third-generation Low-E³ glass with a triple layer of silver. - **Jada.** Jada says argon improves performance in a 1/2 inch air space. Its NFRC samples use a Technoform TGI spacer and argon fill. See the table below. - **Bertrand.** Bertrand publishes U-values for several systems and says it takes part in the NFRC program. Metal frames need a thermal break too. ENERGY STAR notes that aluminum frame design “typically includes thermal breaks to reduce conductive heat loss through the metal.” Read [thermally broken steel windows](https://honeyrock.multisites.ai/guides/thermally-broken-steel-windows) for the steel version of that story. ![Afternoon light through a wall of glass](https://honeyrock.multisites.ai/_astro/light-living-glass-wood-ceiling-01.DVsux7tl_ZNR1iR.avif) ## Which ENERGY STAR climate zone is Dallas in? ENERGY STAR places Dallas County and Tarrant County, which includes Fort Worth and Southlake, in its Southern zone. Collin and Denton counties, which cover Plano and Frisco, fall in the South-Central zone. Confirm your address in the official finder before you buy. ENERGY STAR says it is “important to select windows, doors, or skylights that are suited to the type of climate you live in.” Its limits vary by zone. The current ENERGY STAR page shows those limits as pictures, so this page does not print the numbers. Read the limits for your zone on the ENERGY STAR site, and see [ENERGY STAR climate zone](https://honeyrock.multisites.ai/glossary/energy-star-climate-zone) in the glossary. The county list comes from the climate zone spreadsheet that ENERGY STAR links from its finder, read in November 2026. Zones can change when ENERGY STAR updates its rules, so recheck before you order. Frisco spans two counties, so a Frisco address needs a finder check. ## How do I read an NFRC label? An NFRC label reports the whole window’s tested ratings. DOE says all qualifying ENERGY STAR units “must be certified and labeled by NFRC,” and that labels “typically report VT.” Compare labels for the exact size, glass and grid pattern you plan to buy. Jada gives a useful warning on this point. It tells buyers to confirm that quoted values are “for the unit value and not the center of glass values.” Center-of-glass numbers look better because they leave out the frame. Always ask which one you are reading. Our guide on [how to read an NFRC label](https://honeyrock.multisites.ai/guides/how-to-read-an-nfrc-label) walks through each line. The glossary entry for the [NFRC label](https://honeyrock.multisites.ai/glossary/nfrc-label) is a short version. ## What do Jada, Sun and Bertrand publish? Each maker publishes something different. Jada lists NFRC sample ratings. Sun describes its glass and spacers but lists no U-factors on the pages we read. Bertrand lists U-values in its own units. Compare only like with like, and ask for NFRC data on your exact product. Maker Published item Value as published Note Jada NFRC sample, outswing window, column Clr-NG U-factor 0.37, SHGC 0.28 Sample glass: 1/4 inch over 1/4 inch unit, Technoform TGI spacer, argon fill Jada NFRC sample, outswing window, column IS20-SDL U-factor 0.35, SHGC 0.25 Same sample build; grid and glass change the result Jada NFRC sample, direct-set fixed, column IS20-NG U-factor 0.26, SHGC 0.32 A fixed unit, shown for comparison Sun Sun Advantage 270 Low-E² and 366 Low-E³ No U-factor or SHGC on the pages read Sun describes the coatings and visible light share in words Bertrand Synergic, triple and double glazing U factor 0,16 and 0,26, “confirmed by NFRC” Bertrand’s own wording and comma style Bertrand Linear U-value 0.73 W/(m²K) A metric value, not the U.S. U-factor on a label Jada’s page also says “swing products tend to rate better than sliding or folding products,” and that true divided lites rate lower than simulated ones. Both points help when you pick a window style. Read the [Jada partner page](https://honeyrock.multisites.ai/our-partners/jada), the [Sun Windows partner page](https://honeyrock.multisites.ai/our-partners/sun-windows) and the [Bertrand partner page](https://honeyrock.multisites.ai/our-partners/bertrand) for the rest of each maker’s data. Honey Rock does not publish its own performance claims. Ask for the NFRC record for the product you choose. ![Rain on a window at night](https://honeyrock.multisites.ai/_astro/detail-rain-on-glass-bokeh-01.C5vQdMwl_PPC5n.avif) ## What energy code applies where I build? It depends on the city. Texas set a statewide residential energy standard, but cities can adopt newer codes. As of November 2026, the cities below publish different editions. Confirm with your city building office, because codes and local amendments change. Place Energy code the city publishes Source type Texas (statewide) 2015 IRC, Chapter 11, effective Sept. 1, 2016 Texas Comptroller, SECO Dallas 2021 International Energy Conservation Code with Dallas amendments City of Dallas Southlake 2021 International Energy Conservation Code City guideline PDF Highland Park 2024 IECC, as amended Town builders packet Frisco 2024 IECC with amendments, effective 06-02-2026 City adopted codes page Fort Worth 2015 Energy Conservation Codes City building and energy codes page The U.S. DOE lists the current state code for Texas as the 2015 IECC. The Texas Comptroller’s State Energy Conservation Office reviews residential codes on a six-year cycle. The metro does not share one code. Frisco lists 2024 while Fort Worth lists 2015, so always say which city. Read more in our post on [DFW energy codes and new windows](https://honeyrock.multisites.ai/blog/dfw-energy-codes-and-new-windows) and the [Dallas page](https://honeyrock.multisites.ai/areas/dallas), [Southlake page](https://honeyrock.multisites.ai/areas/southlake) and [Fort Worth page](https://honeyrock.multisites.ai/areas/fort-worth). Plano, McKinney and other cities are not in the table. Check with that city’s building office for its edition. ## What does Highland Park ask for on its plan checklist? Highland Park’s residential builders packet asks for window and door sizes with SHGC and U-factor, and lists “(SHGC < 0.25 max & U-Factor < 0.35 max).” It also asks for 2024 IECC compliance signed by an energy consultant with ICC certification. As of November 2026, that is what the packet says. This is a plan-submittal checklist for residential permits. Whether it applies to a single window swap is not clear from the packet, so ask the Town. Read our post on [Highland Park window and door permits](https://honeyrock.multisites.ai/blog/highland-park-window-and-door-permits) and the [Park Cities page](https://honeyrock.multisites.ai/areas/park-cities). A checklist limit of “less than 0.25” is strict. Jada’s lowest published SHGC sample for a window is 0.25, which does not sit under that line. That does not rule Jada out. It shows why you should get the NFRC value for the exact glass package before you submit plans. ![A farmhouse with a pool at dusk](https://honeyrock.multisites.ai/_astro/dusk-farmhouse-aerial-pool-01.BDzXIkRa_1d5AK0.avif) ## Is there still a federal tax credit for windows? No. The IRS says: “You can claim the credit for improvements made through December 31, 2025.” That date has passed, so the federal energy efficient home improvement credit no longer applies to new window work. Do not plan a budget around it. Read our short post on [the federal window tax credit that ended](https://honeyrock.multisites.ai/blog/federal-window-tax-credit-ended). Utility or city programs may exist, and their terms change. Ask your utility directly. This page is not tax or legal advice. ## What should I ask before I order energy-efficient windows? Ask for numbers you can check and a spec that fits each face of the house. Request the NFRC label values, the glass makeup, the spacer and fill, and the code your city enforces. Put the answers in writing. 1. What are the NFRC U-factor, SHGC and VT for this exact unit, with sash and frame? 2. Does the number include the grid pattern I chose? 3. What glass will I get on the west and east faces, and why? 4. Is the frame thermally broken? What spacer and fill does the unit use? 5. Which energy code does my city enforce, and does my permit need a compliance report? 6. Does the unit need ENERGY STAR certification for my zone, and does the maker list it? 7. What does the maker warrant for glass seals and finish? Our [glass options guide](https://honeyrock.multisites.ai/guides/glass-options-for-windows-and-doors) and [planning a window and door project](https://honeyrock.multisites.ai/guides/planning-a-window-and-door-project) help you prepare. For historic homes, check approvals first in [windows in Dallas historic districts](https://honeyrock.multisites.ai/guides/windows-in-dallas-historic-districts). ## Next step Tell Honey Rock which faces of your house get the most sun and which makers interest you. Start at the [windows overview](https://honeyrock.multisites.ai/windows) and the [energy-efficient windows page](https://honeyrock.multisites.ai/energy-efficient-windows-texas), then [start your project](https://honeyrock.multisites.ai/contact-us) or call (214) 484-9982. ## Questions people ask ### What window efficiency ratings should I look for in Texas? Look for a low SHGC first, then a low U-factor, and check visible transmittance so rooms stay bright. ENERGY STAR sets limits by climate zone, and Dallas and Tarrant counties are in the Southern zone. Ask for the NFRC label values for the exact unit, not a sample. ### What is SHGC and why does it matter in Texas? SHGC is the share of the sun's heat that passes through the window, from 0 to 1. A lower number means less heat gets in. In North Texas, where the average first 100°F day at DFW Airport is July 1, a low SHGC cuts the cooling load. ### What is a good U-factor for windows? A lower U-factor means less heat flows through the window. The right target depends on your zone and your code. ENERGY STAR sets zone limits, and some towns set their own. Highland Park's plan checklist, for example, lists a U-factor under 0.35. ### Do new windows help with Texas heat? They can. Low-E coatings and a low SHGC cut sun heat, and argon fill and warm-edge spacers cut heat flow at the glass. Frames, air leaks and shade also matter. A new window with the wrong glass for your sun face will disappoint. ### What does an NFRC label tell me? It reports the ratings for the whole window as tested: U-factor, SHGC and visible transmittance, and often air leakage. DOE says all qualifying ENERGY STAR units must be certified and labeled by NFRC. Compare labels, not brochure claims. ### Can I still get a federal tax credit for windows? No, not for new work. The IRS says you can claim the energy efficient home improvement credit for improvements made through December 31, 2025. Today is after that date. Ask a tax professional about your own situation. ## Terms on this page - [SHGC (Solar Heat Gain Coefficient)](https://honeyrock.multisites.ai/glossary/shgc) - [Visible transmittance (VT)](https://honeyrock.multisites.ai/glossary/visible-transmittance) - [ENERGY STAR climate zone](https://honeyrock.multisites.ai/glossary/energy-star-climate-zone) - [Thermally broken steel](https://honeyrock.multisites.ai/glossary/thermally-broken-steel) - [Argon gas fill](https://honeyrock.multisites.ai/glossary/argon-gas-fill) - [Low-E coating](https://honeyrock.multisites.ai/glossary/low-e-coating) - [Thermal break](https://honeyrock.multisites.ai/glossary/thermal-break) - [NFRC label](https://honeyrock.multisites.ai/glossary/nfrc-label) - [U-factor](https://honeyrock.multisites.ai/glossary/u-factor) - [Sash](https://honeyrock.multisites.ai/glossary/sash) ## Sources 1. [U.S. Department of Energy: Purchasing Energy-Efficient Residential Windows, Doors, and Skylights](https://www.energy.gov/cmei/femp/purchasing-energy-efficient-residential-windows-doors-and-skylights) 2. [U.S. Department of Energy: Purchasing Energy-Efficient Residential Windows, Doors, and Skylights (climate)](https://www.energy.gov/cmei/femp/purchasing-energy-efficient-residential-windows-doors-and-skylights) 3. [U.S. Department of Energy: Purchasing Energy-Efficient Residential Windows, Doors, and Skylights (U-factor)](https://www.energy.gov/cmei/femp/purchasing-energy-efficient-residential-windows-doors-and-skylights) 4. [U.S. Department of Energy: Purchasing Energy-Efficient Residential Windows, Doors, and Skylights (SHGC)](https://www.energy.gov/cmei/femp/purchasing-energy-efficient-residential-windows-doors-and-skylights) 5. [U.S. Department of Energy: Purchasing Energy-Efficient Residential Windows, Doors, and Skylights (hot climates)](https://www.energy.gov/cmei/femp/purchasing-energy-efficient-residential-windows-doors-and-skylights) 6. [U.S. Department of Energy: Purchasing Energy-Efficient Residential Windows, Doors, and Skylights (tints)](https://www.energy.gov/cmei/femp/purchasing-energy-efficient-residential-windows-doors-and-skylights) 7. [U.S. Department of Energy: Purchasing Energy-Efficient Residential Windows, Doors, and Skylights (visible transmittance)](https://www.energy.gov/cmei/femp/purchasing-energy-efficient-residential-windows-doors-and-skylights) 8. [U.S. Department of Energy: Purchasing Energy-Efficient Residential Windows, Doors, and Skylights (low VT)](https://www.energy.gov/cmei/femp/purchasing-energy-efficient-residential-windows-doors-and-skylights) 9. [U.S. Department of Energy: Purchasing Energy-Efficient Residential Windows, Doors, and Skylights (features)](https://www.energy.gov/cmei/femp/purchasing-energy-efficient-residential-windows-doors-and-skylights) 10. [U.S. Department of Energy: Purchasing Energy-Efficient Residential Windows, Doors, and Skylights (labels)](https://www.energy.gov/cmei/femp/purchasing-energy-efficient-residential-windows-doors-and-skylights) 11. [U.S. Department of Energy: Purchasing Energy-Efficient Residential Windows, Doors, and Skylights (label VT)](https://www.energy.gov/cmei/femp/purchasing-energy-efficient-residential-windows-doors-and-skylights) 12. [ENERGY STAR: Windows, Doors, and Skylights Climate Zone Finder](https://www.energystar.gov/products/building_products/residential_windows_doors_and_skylights/climate_zone/search) 13. [ENERGY STAR: What makes it ENERGY STAR?](https://www.energystar.gov/products/res_windows_doors_skylights/key-product-criteria) 14. [NWS Fort Worth: DFW 100 Degree Day Summary](https://www.weather.gov/fwd/d100info) 15. [NWS Fort Worth: DFW 100 Degree Day Summary (record)](https://www.weather.gov/fwd/d100info) 16. [NWS Fort Worth: DFW Normals, Means, and Extremes (cooling)](https://www.weather.gov/fwd/dfw_records_normals) 17. [NWS Fort Worth: DFW Normals, Means, and Extremes (heating)](https://www.weather.gov/fwd/dfw_records_normals) 18. [NWS Fort Worth: DFW Normals, Means, and Extremes (period)](https://www.weather.gov/fwd/dfw_records_normals) 19. [Texas Comptroller: SECO Single-Family Construction](https://comptroller.texas.gov/programs/seco/code/single-family.php) 20. [U.S. DOE Building Energy Codes Program: Texas](https://www.energycodes.gov/status/states/texas) 21. [City of Dallas: Current City Codes and Ordinances](https://dallascityhall.com/departments/sustainabledevelopment/buildinginspection/Pages/know_code.aspx) 22. [City of Southlake: Accessory Buildings, Additions, and Remodels Guidelines](https://www.cityofsouthlake.com/DocumentCenter/View/45661/Res-Accessory-and-Addition-Guidelines-?bidId=) 23. [City of Frisco: Adopted Codes](https://www.friscotexas.gov/397/Adopted-Codes) 24. [City of Fort Worth: Building and Energy Codes](https://www.fortworthtexas.gov/departments/development-services/permits/building-energy-codes) 25. [Town of Highland Park: Residential Builders Packet](https://www.hptx.org/DocumentCenter/View/8373/Builders-Packet-Residential-PDF) 26. [Town of Highland Park: Residential Builders Packet (energy report)](https://www.hptx.org/DocumentCenter/View/8373/Builders-Packet-Residential-PDF) 27. [Texas Comptroller: SECO Energy Code Adoption](https://comptroller.texas.gov/programs/seco/code/adoption.php) 28. [IRS: Energy Efficient Home Improvement Credit](https://www.irs.gov/credits-deductions/energy-efficient-home-improvement-credit) 29. [Jada Windows: Energy Values (NFRC sample ratings, outswing window)](https://jada.com/features/energy-values) 30. [Jada Windows: Energy Values (NFRC sample ratings, fixed)](https://jada.com/features/energy-values) 31. [Jada Windows: Energy Values (sample glass)](https://jada.com/features/energy-values) 32. [Jada Windows: Glazing](https://jada.com/features/glazing) 33. [Sun Windows: Insulated Glass (argon)](https://www.sunwindows.com/insulated-glass.html) 34. [Sun Windows: Insulated Glass (standard)](https://www.sunwindows.com/insulated-glass.html) 35. [Sun Windows: Duralite Spacer](https://www.sunwindows.com/duralite.html) 36. [Sun Windows: 270 Low-E Glass](https://www.sunwindows.com/glass-270.html) 37. [Sun Windows: 366 Low-E Glass](https://www.sunwindows.com/glass-366.html) 38. [Bertrand: Synergic](https://windowsbertrand.com/offer/synergic) 39. [Bertrand: Linear](https://windowsbertrand.com/offer/linear) 40. [Bertrand: About us](https://windowsbertrand.com/bertrand-about-us) Written by Honey Rock Window and Door and checked against the sources above on November 5, 2026. Product specifications and city rules change, so check the linked page before you act. ## Keep reading - [SHGC and U-factor for Texas: what the numbers should look likeIn Texas, SHGC (how much sun heat gets in) usually matters first, and U-factor (how fast heat leaks through) matters too. The Department of Energy says hot climates need low SHGC. Pick a target from your ENERGY STAR climate zone and your city's energy code, then match it to the rated product.](https://honeyrock.multisites.ai/guides/shgc-and-u-factor-for-texas) - [How to read an NFRC label on a window or doorAn NFRC label lists independent, third-party energy ratings for one window or door: U-factor (heat loss), solar heat gain coefficient (heat from the sun), visible transmittance (daylight) and air leakage. Lower U-factor and SHGC mean less heat moves through. Compare labels for the exact size, glass and frame you plan to buy.](https://honeyrock.multisites.ai/guides/how-to-read-an-nfrc-label) - [Glass options for windows and doors: Low-E, argon, triple and laminatedMost exterior glass is an insulated glass unit: two panes with a sealed, gas-filled gap. Low-E coatings cut heat flow, argon slows convection, a warm-edge spacer protects the edge, and laminated or tempered glass adds sound control or safety. Match the package to each wall, then ask for whole-window ratings.](https://honeyrock.multisites.ai/guides/glass-options-for-windows-and-doors) - [The Federal Window Tax Credit Ended: What Still MattersThe federal Energy Efficient Home Improvement Credit, often called 25C, ended for work after December 31, 2025. The IRS says you can claim it for improvements made through that date, and its Form 5695 instructions say you cannot claim it for property placed in service after. Focus on performance and local code.](https://honeyrock.multisites.ai/blog/federal-window-tax-credit-ended) - [Highland Park Window and Door Permits: What to KnowThe Town of Highland Park requires permits for remodeling, additions and repairs, and says the property owner must make sure a permit is obtained. Its residential builders packet lists window and door sizes with SHGC under 0.25 and U-factor under 0.35 on the plan checklist. Call the Town to confirm your scope.](https://honeyrock.multisites.ai/blog/highland-park-window-and-door-permits) - [Thermally broken steel windows: what the break does and what to askA thermally broken steel window has an insulating barrier between its outer and inner steel halves. The barrier slows heat flow through the metal and helps limit condensation. It does not make a window efficient alone. The glass, spacer and installation set the final NFRC numbers, so judge the whole unit.](https://honeyrock.multisites.ai/guides/thermally-broken-steel-windows) ![A modern home with wide glass doors lit warm at dusk beside a pool](https://honeyrock.multisites.ai/_astro/dusk-modern-home-pool-01.CeePxgPr_Z2giQin.webp) ## Let’s frame your view. Send your plans or a few photos of the openings. We will help you choose the system, the brand and the glass. [Start your project](https://honeyrock.multisites.ai/contact-us)[or call (214) 484-9982](tel:+1-214-484-9982)