Our summers are brutal on garage doors — a west-facing door bakes for hours, and a bare steel panel passes all that heat straight into the garage. Here's what actually holds up and keeps you comfortable.
Material: steel (or faux-wood)
Steel doesn't warp, crack, or fade the way wood can under the Texas sun, and it needs almost no upkeep. If you want the wood look, faux-wood composite gives you the same heat tolerance. Real wood is doable but demands regular refinishing out here.
Insulation: polyurethane, non-negotiable for attached garages
A polyurethane-insulated door (R-12 to R-18) is the single biggest thing you can do to fight the heat — it slows the temperature swing and eases the load on your AC. Here's the full worth-it breakdown, and the best insulation compared.
Color: go lighter
Dark doors look sharp but absorb more heat; lighter colors stay noticeably cooler in direct sun. If your door faces west or south, lean lighter.
Put it together
Insulated steel, lighter color, quality weather seals. Build that exact door for your opening in our designer, or let us install it — we'll help you pick the right R-value without overselling.
R-value vs. U-factor: which one measures a door
For garage doors, R-value and U-factor are not the same thing, and the difference matters. A door’s advertised R-value is calculated at the center of one section, not measured across the whole door. U-factor is the measured, whole-door number that building codes use — and for U-factor, lower is better.
- R-value on a garage door is a calculation of one section’s center; DASMA says that method ‘should not be used for garage door assemblies.’ DASMA TDS-163
- U-factor is the whole-door measurement (ANSI/DASMA 105) that captures joints, seals and hardware — and lower is better. DASMA TDS-163 Amarr
- For garage doors, R-value ≠ 1/U-factor. They are not reciprocals. DASMA TDS-163
- Clopay’s polyurethane Intellicore doors range from about R-6.3 to R-20.4 depending on the line. Clopay
- ENERGY STAR does not certify garage doors at all — it covers windows, entry doors and skylights, rated by U-factor. An ‘ENERGY STAR-rated garage door’ claim is incorrect. ENERGY STAR
| R-value | U-factor | |
|---|---|---|
| What it measures | Center of one door section (calculated) | The whole installed door (measured) |
| Test method | Component calculation | ANSI/DASMA 105 |
| Used by building codes | No (not for assemblies) | Yes |
| Better when… | Higher | Lower |
“U-factor provides the highest degree of confidence when evaluating and comparing the thermal performance of garage door assemblies.”
In Texas heat, an attached garage’s door is part of your home’s thermal envelope. DOE guidance focuses on air-sealing and insulating between an unconditioned garage and the living space, and defers R-value targets to the IECC climate-zone tables rather than a single garage-door number. U.S. DOE
Sources: DASMA TDS-163 · Amarr · Clopay · ENERGY STAR · U.S. DOE
Key takeaways
- Best combo for Texas: insulated polyurethane steel in a lighter color.
- Steel (or faux-wood) resists the heat damage that hurts real wood.
- Polyurethane insulation (R-12 to R-18) is the biggest heat-fighter.
- Lighter colors run cooler than dark ones in direct sun.
- For an attached garage, insulation is the upgrade that pays off every summer.