Beta These tools are in active development. Try them out and share your feedback.
Open Source · MIT License

Modern tools for building energy simulation

A suite of open-source tools for EnergyPlus — from a Python library to a visual web editor to AI integration. Everything you need to model, simulate, and optimize building energy performance.

4000x Faster lookups
55k+ Weather stations
25 AI tools via MCP
Solar Alt 42.3°
Azimuth 187.2°
Surf Temp 24.7 °C
Wind 3.2 m/s
Heat Flux +12.4 W/m²
Envelope ΔT 6.8 K

One ecosystem.
One mission.

From Python scripting to visual editing to AI-powered workflows — choose the tools that fit your needs.

Python
Core Library

idfkit

A fast, modern Python toolkit for EnergyPlus with O(1) lookups, automatic reference tracking, and zero dependencies.

  • O(1) dictionary-based object indexing
  • Live cross-object reference graph
  • IDF + epJSON dual format support
  • 3D geometry & thermal calculations
  • Sync, async & batch simulation
  • EnergyPlus 8.9 through 25.2
pip install idfkit
View on GitHub
MCP Server
AI Integration

idfkit-mcp

An MCP server that exposes building energy modeling to AI agents. Let Claude author, validate, and simulate EnergyPlus models.

  • 25 MCP tools for full workflow
  • Schema discovery & validation
  • Model authoring & modification
  • Weather station integration
  • Simulation execution & results
  • stdio & HTTP transport modes
uvx idfkit-mcp
View on GitHub
Reference
Documentation

idfkit-docs

Interactive EnergyPlus Input/Output reference documentation. Browse object types, fields, and constraints — all searchable and hyperlinked.

  • Searchable object type reference
  • Field-level docs with units & constraints
  • Hyperlinked cross-references
  • Built with Zensical
docs.idfkit.com
VS Code
Editor Extension

idfkit-lsp

Language Server and VS Code extension for intelligent idfkit editing. Autocomplete, hover docs, signature help, and AST-based type inference.

  • Object type & field autocomplete
  • Inline hover documentation
  • Signature help for doc.add() calls
  • AST-based type inference
  • VS Code extension included
  • Python 3.10+ / pygls
pip install idfkit-lsp
View on GitHub

Built for performance.
Designed for humans.

Legacy tools hold you back. idfkit is built from the ground up for speed, correctness, and developer experience.

4,000x faster

O(1) dictionary-based lookups vs linear scans. On a 1,700-object IDF, idfkit is 4,000x faster than eppy.

Reference tracking

Automatic live graph of cross-object relationships. Rename a zone and every reference updates instantly.

Zero dependencies

Core library uses only the Python standard library. Optional extras for pandas, plotting, and cloud storage.

3D geometry

Built-in Vector3D and Polygon3D classes. Calculate surface areas, zone volumes, and coordinate transforms natively.

55,000+ weather stations

Search by location or coordinates. Download EPW and DDY files. Inject design days automatically.

AI-native

MCP server with 25 tools lets AI agents author, validate, and run energy simulations autonomously.

Browser-native simulation

Run EnergyPlus simulations directly in the browser via Envelop. No installation, no server — just open and simulate.

Intelligent code editing

Autocomplete, hover docs, signature help, and AST-based type inference for IDF files in VS Code.

Interactive documentation

Searchable, hyperlinked EnergyPlus I/O reference with field constraints and cross-references — all in the browser.

Up and running
in seconds.

quickstart.py
# Install
pip install idfkit

# Load a model
from idfkit import load

model = load("building.idf")

# O(1) lookup by name
zone = model["Zone"]["Office_Floor_1"]

# Automatic reference tracking
zone.name = "Main_Office"
# ^ All referencing objects update automatically

# Run simulation
results = model.simulate()
print(results.summary())
claude_desktop_config.json
// Add to your Claude MCP config
{
  "mcpServers": {
    "idfkit": {
      "command": "uvx",
      "args": ["idfkit-mcp"]
    }
  }
}

// Then ask Claude:
// "Create an office building model
//  with 3 zones and run an annual
//  simulation for Denver, CO"
No installation needed
# Envelop runs entirely in your browser

1. Open Envelop in any modern browser
2. Import an IDF or start from scratch
3. Design HVAC systems visually
4. Edit schedules with intuitive UI
5. View 3D geometry in real-time
6. Simulate with in-browser EnergyPlus

# Powered by WebAssembly
# No server required
# Works offline

Help shape the future
of energy modeling.

All tools are in active beta. We'd love for you to try them and let us know what's working and what isn't.

idfkit

Core Python library

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Envelop

Web-based visual editor

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idfkit-mcp

AI integration via MCP

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idfkit-docs

Reference documentation

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idfkit-lsp

VS Code extension

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Have a feature request or general feedback?