DesignBuilder
- Uses EnergyPlus
EnergyPlus
- EnergyPlus™ is a whole building energy simulation program that engineers, architects, and researchers use to model both energy consumption—for heating, cooling, ventilation, lighting and plug and process loads—and water use in buildings.
- Calculates loads using the Heat Balance (HB) Method and, so, follows the current best practice per ASHRAE Handbook Fundamentals and meets the requirements of Title 24.
- EnergyPlus
eQUEST
- For HVAC Load Calculations, eQUEST uses the DOE-2 calculation engine which does not use the ASHRAE Heat Balance Method and, so, is not Title 24-compliant for load analysis. eQUEST relies on a pre-calculated, simplified weighting factor approach derived from ASHRAE principles, not the direct, hourly heat balance method that defines newer programs like EnergyPlus.
IES Virtual Environment
OpenStudio
- Conceptually, OpenStudio SDK provides an Application Programming Interface (API) to access the EnergyPlus modeling engine. This interface provides many benefits such as a stable, version-controlled interface, space typology abstractions that make it easier for end-users to model buildings, and language bindings in Ruby, Python and C-Sharp to make it more accessible to users familiar with these languages. The CLI is a powerful, cross-platform tool that allows users to run OpenStudio based workflows on supported architectures such as Linux, Windows and Mac.
Trane Trace 3D Plus
Title 24 Compliance Software
Approved for the 2025 version of Title 24 as of January 2026:
CBECC
- CBECC: California Building Energy Code Compliance (for Nonresidential and Multifamily buildings) software
- Built on top of EnergyPlus
- Title 24 Nonresidential Compliance Software
EnergyPro
- EnergySoft
- Available for purchase are modules to perform HVAC load calculations for residential and commercial buildings