Early-stage energy analysis software for architects

Trimble · SketchUp and Revit plugins, plus a web app · US$1,995 per user per year; enterprise and education plans on request

Architects modelling concept massing in SketchUp or Revit who want annual energy and daylight results within minutes.

• Hour-by-hour annual simulation with EnergyPlus and Radiance, run from simple SketchUp or Revit geometry.
• Results for energy use and carbon emissions, thermal comfort, daylight (daylight factor, direct sun exposure and spatial daylight autonomy) and preliminary HVAC sizes.
• A cloud web app compares HVAC systems and natural ventilation strategies and shares projects with the team.

Good to know

• Needs SketchUp 2024 to 2026 or Revit 2023 to 2025; the Revit plugin is Windows-only, and an internet connection is required.
• Available only in English.

Visit Sefaira

Embrace Ideas · Web app, in the browser · Free plan; paid plans from €59/month (cancellation takes effect after 12 billing cycles) or €599/year, with a 7-day free trial

Testing how orientation, building shape and thermal mass affect energy use on a specific site, before any geometry exists.

• A preliminary hourly, multi-zone heat balance on the site's weather data, with monthly energy use, zone loads and end uses; inputs include orientation, aspect ratio, thermal mass, floor area, floors, floor height, window-to-wall ratio and use type.
• The Free plan includes it on the nearest weather station's data; paid projects save the building parameters and add site-specific data and present-versus-future comparisons.
• Projects on paid plans sweep 221 combinations of orientation (-90° to +90°) and aspect ratio (1 to 5) and compare their energy use intensity.
• Sits next to the climate analyses that explain the numbers: passive strategies on the psychrometric chart, solar radiation, PV potential and national grid carbon intensity.

Good to know

• A preliminary analysis, not a detailed or compliance energy model: it works from a few parameters rather than a 3D model, and window-to-wall ratio and shading are not part of the optimisation.
• The technical energy balance, with the full set of inputs (assemblies, setpoints, COP and zoning), is on the Technical and Enterprise plans, which are quoted individually.

Integrated Environmental Solutions (IES) · Desktop simulation suite (Windows) · Price on request; free, fully featured trial

Teams that want one integrated environment from feasibility through detailed design, compliance and operation.

• IES presents the VE for use from high-level prototyping at feasibility through technical design, covering energy, comfort and whole-life carbon.
• Parametric simulation compares design options on operational energy, carbon emissions and energy cost.
• iCD, a SketchUp plugin, gives rapid energy and carbon estimates for single buildings and portfolios.

Good to know

• Runs on Windows; on a Mac it needs Windows through VMware Fusion, Parallels Desktop or Boot Camp, and Linux is not supported.

Visit IESVE

DesignBuilder Software Ltd · Desktop software (Windows) · Architectural packages from €1,225/year (Essentials) or €1,725/year (Plus); free 30-day evaluation

Architects who want one EnergyPlus model that starts simple at concept stage and grows with the design.

• EnergyPlus and Radiance behind a 3D modeller; import models from BIM tools such as Revit, or draw directly.
• You choose the level of detail for each design stage, so the concept model is developed rather than rebuilt.
• Energy, comfort, cost and daylighting results, with parametric optimisation diagrams, data plotted on the model and solar shading diagrams.

Good to know

• Windows software; the recommended hardware is a Windows 11 PC with four or more cores and 16 GB of RAM.
• Optimisation, CFD and certification are separate modules that not every package includes.

Visit DesignBuilder

Solemma LLC · Rhino plugin (Windows) · Price on request; free trial for firms

Rhino users who need energy, daylight and glare results from the same model.

• Energy modelling built on EnergyPlus, with daylight and glare simulation based on Radiance path tracing.
• Zone-level thermal comfort results based on PMV, plus hourly ASHRAE adaptive comfort metrics for export.
• A weather browser with more than 30,000 weather files.

Good to know

• Requires a licensed Windows version of Rhino 6, 7 or 8; it does not run on the macOS version of Rhino.

Visit ClimateStudio

Ladybug Tools LLC · Grasshopper plugin (Rhino), open source · Free and open source; Rhino needs its own licence

Parametric energy and daylight studies on Grasshopper geometry, for teams comfortable with visual scripting.

• Creates, runs and visualises EnergyPlus and OpenStudio energy models and Radiance daylight simulations from Grasshopper.
• Heating and cooling energy, HVAC sizing, energy balance, passive and active strategies and indoor comfort.
• Parametric scripting lets you explore many design options and automate studies.

Good to know

• Ladybug Tools describes Honeybee's detailed modelling as most relevant during the mid and later stages of design.
• Requires Rhino, Grasshopper and visual-scripting skills.

Visit Honeybee (Ladybug Tools)

The OpenStudio Coalition · Desktop app (Windows, macOS and Linux), open source · Free

A free graphical interface for building complete EnergyPlus models, including HVAC systems, loads and schedules.

• A graphical interface to OpenStudio models: envelope, loads, schedules, geometry, HVAC and OpenStudio Measures.
• Built on the OpenStudio SDK, which supports EnergyPlus energy modelling and Radiance daylight analysis.
• Latest release listed on GitHub: 1.11.1 (June 2026).

Good to know

• Free, but the current version is downloaded by logging in to the OpenStudio Coalition site; recent GitHub releases have no installers attached.
• Maintained by the OpenStudio Coalition and community contributors since NREL's final release of the application in April 2020.

Visit OpenStudio Application

US Department of Energy (DOE) · Simulation engine (Windows, macOS and Linux) · Free; source code on GitHub

The engine for detailed whole-building energy simulation, run directly or through one of the interfaces on this page.

• Whole-building simulation of energy use and water use, for engineers, architects and researchers.
• Runs underneath Sefaira, DesignBuilder, ClimateStudio, Honeybee, OpenStudio and BEopt.
• Latest release listed on GitHub: 26.1.0 (March 2026), with builds for Windows, macOS and Linux.

Good to know

• Its documentation describes it as a simulation engine designed to sit behind a graphical interface; run on its own, it uses input files and the EP-Launch utility.

Visit EnergyPlus

National Laboratory of the Rockies (NLR, formerly NREL) · Desktop software (Windows) · Free download

Residential projects that need cost-optimal efficiency packages, from single-family homes to multifamily units.

• Evaluates single designs, parametric sweeps and cost-based optimisation, for new homes and retrofits.
• Runs EnergyPlus through OpenStudio-HPXML, with assumptions based on ANSI/RESNET/ICC standards and the Building America protocols.
• Version 3.1.1 Beta released on 14 May 2026.

Good to know

• Designed for residential buildings and available only for Windows; NLR notes Mac users have run it in a virtual machine or on a cloud Windows workstation.
• NLR notes its built-in option costs date from around 2015 and should not be used for analysis; enter your own cost data.

Visit BEopt