Big Ladder Software

Welcome to Big Ladder!

We are a Denver-based company dedicated to providing software and services for the building energy modeling industry. The company name reflects our mission to “help our clients reach new heights”.

Peter Ellis, President of Big Ladder, founded the company in 2009 after a six-year career at the National Renewable Energy Laboratory in Golden, Colorado. Today we are a team of programmers, engineers, and scientists with a unique combination of expertise in software development, computer simulation, and building science. Over the past several years, the company has experienced steady growth and achieved significant success and recognition in the industry.

We specialize in all things related to the EnergyPlus simulation engine. We provide software tools, training, support, and consulting services for EnergyPlus to mechanical, architectural, and design engineering firms across the US.

Software Tools

As a software company we handle all phases of software development: design, implementation, testing, documentation, support, and training. We have a special passion for open-source software. Our current open-source projects include Elements, Kiva, Modelkit/Params, Euclid, and an Atom package for EnergyPlus.

As members of the EnergyPlus Development Team, we have over 15 years of collective experience programming EnergyPlus. We have been involved with developing component algorithms, user interfaces, and other tools for EnergyPlus. As developers we are able to delve into the program source code to help debug users’ problems.

Training Services

We currently offer various training workshops for professionals on a training platform that hosts workshop files and other materials. We use this platform to deliver public and private (in-house) workshops via webinar or in-person formats. We have trained hundreds of new users in the intricacies of EnergyPlus in workshops at US and international locations.

Workshop topics include:

  • EnergyPlus

  • Our Modelkit framework we have developed for efficient parametric building energy modeling with EnergyPlus

  • OpenStudio Application

  • DesignBuilder (we are authorized through DesignBuilder Software (UK) as the official training providers for DesignBuilder in the US)

  • California Simulation Engine (the underlying simulation engine used for residential building design and compliance evaluation in California via CBECC-Res)

To read more about workshop topics we offer, please visit our training page.

Support Services

We offer hourly support services for EnergyPlus and OpenStudio by phone and by email. We are licensed through the National Renewable Energy Laboratory as official support providers for OpenStudio.

Consulting Services

We exclusively use EnergyPlus and OpenStudio to perform whole-building energy modeling and have modeled numerous real-world buildings ranging from commercial to residential to US Army buildings. We specialize in complex projects and large-scale projects such as technology screening studies and market sector analyses.


For more information, contact us at: