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Hayes Zirnhelt

Sr. Associate


Hayes is a Sr. Associate in RMI’s Building Practice, focusing on getting to deeper savings through energy modeling, working on advancing energy modeling practices, and designing and evaluating strategies to achieve deep savings in new and existing buildings individually and across portfolios. He has a background in green building design and building energy simulation.


Hayes studied Integrated Engineering at the University of British Columbia where he focused on energy and environmental engineering. Following this he completed his Masters degree at Ryerson University with a focus on calibrated whole building energy simulation and passive solar housing. Hayes then started his own building energy analysis practice and worked on several super efficient building projects as well as taught an advanced building energy simulation workshop at Ryerson University. He also has experience working for the Pembina Institute – a non-profit energy policy think tank located in Canada, where he developed a building stock model to assess the impact of cutting edge green building policies. Hayes also has construction experience, and has built his own passive solar, off-grid home.

Select RMI Projects

Uncertainty Analysis – As part of RMI’s work to increase investor confidence and advance energy modeling practices, Hayes had a primary role in the development of uncertainty analysis workflow methodology which enables modelers to predict energy consumption as a probably range rather than a single value, accounting for uncertainty in model inputs. He has given presentations and training on this topic.

The Exchange – Hayes worked on the energy analysis for the Exchange retail portfolio, using energy modeling to develop replicable pilot projects, and is leading the development of a portfolio retrofit strategy based on individual building analysis and capital and operational considerations.

CU Boulder – Hayes provided energy modeling expertise to two deep retrofit pilots at CU Boulder, helping to evaluate a number of advanced energy savings strategies and provided training in OpenStudio / EnergyPlus to allow the team to analyze deeper savings measures that wouldn’t otherwise be considered.


  • Master of Applied Science, Building Science Program, Ryerson University, 2013
  • Bachelor of Applied Science, Integrated Engineering Program, University of British Columbia, 2010

Professional Affiliations

  • International Building Performance Simulation Association (IBPSA) – U.S and Canadian Chapters

Publications and Presentations

  • Zirnhelt H., Bridgeland, B., and Keuhn, P. (2015): Energy Savings from Window Shades. Prepared for Hunter Douglas by Rocky Mountain Institute.
  • Richman, R., Zirnhelt, H. and Fix, S. (2014). Large-scale building simulation using cloud computing for estimating lifecycle energy consumption. Canadian Journal of Civil Engineering 41(3).
  • Zirnhelt, H., and Richman, R., 2011. Residential Passive Solar Design for Canadian Cities: Assessing the Potential. ISES Solar World Congress, Kassel, Germany. August 28 – September 2, 2011.
  • Zirnhelt, H., and Horne, M. (2010). On-Site Renewable Energy Requirements for Buildings. Discussion Paper for the Pembina Institute’s Municipal Green Building Leaders Project.
  • Zirnhelt, H., and Horne, M. (2010). Energy Labelling and Efficiency Requirements for Existing Buildings. Discussion Paper for the Pembina Institute’s Municipal Green Building Leaders Project.
  • Zirnhelt, H. (2008). Energy and Climate Change at the University of British Columbia. Background Paper for the UBC climate action plan round table.
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