Energy Analysis

Free, open-source EnergyPlus front-end from NREL with a SketchUp plugin, a Measures library for parametric analysis, and Radiance daylighting support.

The free path to professional-grade energy simulation -- NREL's SketchUp plugin makes it accessible solo; expect a learning curve and community-only support.

Free open-source Grasshopper plugins for climate analysis, energy modeling, daylighting, CFD, and urban simulation, with a commercial cloud layer via Pollination.

Best free option for performance-driven design in Rhino/Grasshopper -- 500,000+ downloads, DOE-recognized; solo practitioners get professional daylighting, energy, and CFD for zero cost if they own Rhino.

Free, DOE-funded whole-building energy simulation engine with sub-hourly HVAC, lighting, and water modeling -- the engine under most commercial tools on this list.

Use it directly only if you need IDF-level scripting control or parametric Python runs; otherwise reach it through DesignBuilder, OpenStudio, or Sefaira.

Cloud-based AI platform for early-stage urban design, massing, and microclimate analysis.

Situational for teams already in the Autodesk ecosystem -- Forma's cloud microclimate analysis (wind, daylight, sun hours, noise) adds environmental performance insight at the massing stage without a separate energy tool, but only relevant for projects large enough to require early-stage climate analysis.

EnergyPlus-based building simulation software with a graphical interface for energy, daylighting, HVAC, CFD, and LEED/BREEAM compliance.

Best value for a solo engineer doing energy compliance -- transparent modular pricing lets you buy only what you need; $975/yr for the core simulation module is the most honest pricing on this list.

Whole-building simulation suite covering thermal, HVAC, daylighting, CFD, and compliance for LEED, BREEAM, and Passivhaus.

The most comprehensive simulation suite on this list -- but the learning curve and quote-only pricing make it overkill for most solo architects; better fit for solo MEP engineers doing compliance.

Rhino and Grasshopper plugin for daylighting, annual glare, energy modeling, and PV analysis using a novel path-tracing Radiance engine.

Best-in-class daylighting simulation for Rhino users -- meaningfully faster than legacy Radiance workflows; pass if you don't work in Rhino or can't justify opaque pricing.

SketchUp-integrated energy and daylighting analysis plugin that runs full annual EnergyPlus and Radiance simulations without leaving the modeler.

Best energy analysis option for SketchUp users -- skip if your workflow is Revit or Rhino, the integration doesn't follow you.