Accepting Better Building Simulation Outputs

This document is written for the people who review building permit applications: plan reviewers, building inspectors, and energy code specialists working in city or county building departments. You're the ones who have to decide whether a compliance submittal is legitimate or creative fiction.

In most jurisdictions, you're called the Authority Having Jurisdiction, or AHJ for short. That's code-speak for "the person who can say no to a building permit." Sometimes you work for a municipal building department, sometimes for a county, occasionally for a state agency. Regardless of the org chart, your job is the same: verify that proposed buildings meet adopted energy codes before construction starts.

You didn't necessarily sign up to become an expert in building energy simulation, but performance-based compliance keeps showing up in your inbox anyway. Here's why Better Building simulation outputs meet the technical requirements you need to approve them.

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Validation Against ANSI/ASHRAE Standard 140-2020

Better Building's simulation engine has been validated against ANSI/ASHRAE Standard 140-2020, the industry standard method for testing building energy analysis software. This isn't a checkbox exercise. Standard 140 puts simulation engines through a rigorous set of comparative tests that expose whether the underlying physics are implemented correctly.

The standard tests envelope loads, HVAC performance, shading algorithms, and thermal mass calculations against both analytical solutions and empirical data. Software that passes these tests produces results within acceptable tolerance ranges, meaning the simulation outputs reflect real building physics rather than wishful thinking or programming errors.

This validation matters for code compliance work because it demonstrates that the tool calculates energy performance correctly across the range of building types and systems you'll actually see in practice. Standard 140 compliance is recognized by DOE's Building Energy Codes Program and is frequently cited in state energy code adoption processes. When a modeling tool has passed Standard 140, it means someone has already done the technical vetting work you'd otherwise have to take on faith.

EnergyPlus v25.1 as the Calculation Engine

Better Building uses EnergyPlus v25.1 for all energy simulations. EnergyPlus is developed and maintained by the U.S. Department of Energy and has been the reference simulation engine for building energy modeling for over two decades. It's the same engine used by REScheck, COMcheck, and many commercial energy modeling tools you'd encounter in a typical submittal.

EnergyPlus v25.1 implements the calculation methods specified in ASHRAE 90.1 Appendix G and supports both the Energy Cost Budget Method (Section 11) and the Performance Rating Method. The algorithms are peer-reviewed, extensively documented, and updated regularly to align with current code requirements.

Using a current version (v25.1 was released in 2025) means the software includes the latest updates for equipment performance, climate data, and modeling procedures. Older versions sometimes miss edge cases or contain bugs that have since been corrected. Current software reduces the likelihood of compliance issues caused by outdated calculation methods.

Practical Implications for Plan Review

From a review standpoint, accepting Better Building outputs doesn't require learning a new compliance framework. The platform generates the same documentation you'd see from any other ASHRAE 90.1 performance-based compliance package: baseline and proposed building models, energy cost comparisons, and compliance forms. The underlying calculations follow the same procedures whether they're run through Better Building, a consultant's modeling software, or any other validated tool.

The combination of Standard 140 validation and EnergyPlus ensures that simulation results are reproducible and defensible. If questions arise during review, the methodology is transparent and the calculation engine is publicly documented. This makes verification straightforward compared to proprietary tools with black-box algorithms.

You can't personally re-run every energy model that crosses your desk. Nobody has time for that. What you can reasonably expect is that the tool used to generate the model has been validated against recognized standards and uses calculation methods that align with the code you're enforcing. Better Building meets both criteria.

Conclusion

Better Building simulation outputs are built on validated calculation methods (ANSI/ASHRAE Standard 140-2020) using a DOE-maintained simulation engine (EnergyPlus v25.1) that implements ASHRAE 90.1 compliance procedures. These outputs meet the same technical standards applied to submissions from traditional energy modeling consultants and should be accepted for code compliance review on that basis.