There's a quiet thing happening in Texas building codes that affects how comfortable your new home is, how much you spend to live in it every month for the next thirty years, and how it holds its value when you go to sell. Almost nobody talks about it during a walkthrough because it's not as photogenic as the kitchen island. It might matter more than the kitchen island.
If you're touring new builds, or interviewing builders for a custom project, or comparing two homes in the same neighborhood that look identical on the surface — the questions in this post are the ones we'd want our own friends and family asking before they signed anything.
Let's get into it.
The Quiet Code Gap
Here's the situation, in plain English. The Texas statewide minimum energy code is the 2015 International Energy Conservation Code. That code was written more than a decade ago. Most of the rest of the country has long since moved on to the 2021 or 2024 versions, both of which require meaningfully better insulation, tighter construction, more efficient windows, and better mechanical systems than what Texas requires at the state level.
The State Energy Conservation Office has been soliciting stakeholder input on adopting the 2024 IECC, and an update is expected at some point — but as of right now, the official statewide floor is still 2015 code. That's the legal minimum a Texas builder has to meet to deliver a "code-compliant" new home.
It gets more interesting at the city level. Fort Worth uses 2015 IECC with local amendments for its residential energy code. Dallas, just thirty miles east, has adopted the 2021 IECC with its own amendments — a meaningfully more efficient standard. So a new home built in Dallas in 2026 is, all else equal, measurably more efficient than a new home built in Fort Worth to the local minimum.
This doesn't mean every Fort Worth builder is delivering a 2015-vintage home. The good ones are voluntarily building well above local code because they know what their clients deserve and they know what holds up over thirty years. But the ones racing to the bottom on price are absolutely meeting the bare minimum and calling it a finished house.
The questions below help you tell the difference.
Question 1: What's the HERS or ERI Score on This Home?
HERS — the Home Energy Rating System — and ERI — the Energy Rating Index — are standardized scores that measure how energy-efficient a home actually is, on a scale where 100 is a baseline reference home built to a minimum code standard. Lower is better.
A new home that scores in the 60s is solid. A score in the 50s is good. Under 50 is genuinely high-performance. Builders who care about efficiency get their homes rated and can tell you the number. Builders who don't care, can't.
When you ask this question and the builder gives you a confused look, hedges, or says "all of our homes meet code" without giving you a number — that's information. That tells you they're delivering minimum code and they haven't tested the home to know what its actual performance is.
A good builder hears this question and lights up because they've been waiting for someone to ask it.
Question 2: What R-Values Are in the Ceiling, Walls, and Foundation?
R-value measures how well an insulation material resists heat flow. More is generally better, though there are diminishing returns past a certain point. In our climate zone — Climate Zone 3 covers most of DFW — these are the rough benchmarks for a quality new build:
Ceiling insulation should be R-30 to R-49. Anything lower is meeting bare minimum and you'll feel it in summer.
Wall insulation should be R-13 to R-21 depending on framing depth and method. Spray foam, dense-pack cellulose, and thicker batt insulation can all get you into solid territory.
Slab and foundation perimeter insulation should be R-10 or better. This is the part that gets skipped most often in cheaper construction, and it's a real comfort issue if your floors are cold in winter.
These are minimums for a quality build, not maximums. A builder who's serious about performance will exceed these. A builder who's just meeting code will hit them and stop.
Question 3: What's the U-Factor on the Windows?
Windows are usually the weakest thermal point in a home. The U-factor measures how well a window resists heat flow — and this one is opposite of R-value: lower is better.
For our climate, U-0.32 or lower is solid. U-0.28 or lower is excellent. While you're at it, ask about the SHGC — Solar Heat Gain Coefficient. Lower numbers reject more of the sun's heat, which matters tremendously during a Texas summer. SHGC of 0.25 or lower is a meaningful upgrade.
Cheap windows are one of the most common cost-cutting moves in production homebuilding. They look fine. They function fine. They quietly kill your energy bill for thirty years.
