Environmental Simulation in the Design Process

Molly Eagen, AIA

In today's era of changing climate, it is becoming increasingly important to make informed decisions related to building performance in order to achieve goals. Reducing energy consumption is tied to many interrelated factors, including mechanical systems, façade, shell, orientation--and climate.

While research is introducing new technology, building systems and materials that increase energy efficiency, changing climate remains a big variable. Much of our existing infrastructure is planned around historic static climate data. Yet with the increased frequency of 100-year weather events and better data tracking, we cannot assume climate is static, and we are finding that the projected climate changes vary dramatically from region to region.

To address climate challenges, building owners need reliable resources that can accurately predict energy performance through computational simulation--thus reducing energy use and saving money.

We recently presented "Environmental Simulation in the Design Process" at the USGBC Minnesota Chapter 2016 Building Green Conference, highlighting strategies and tools owners and designers can use to simulate climate impact on building performance.

Simulation technology is a growing market with steady development of new and increasingly interactive tools. Matching the right tool with the right design question is the challenge. To help sort through the options and best match design questions with appropriate processes, we presented several Big Ideas about simulation for owners and design teams, among them:


  • Simulation is about changing sustainable design process--to help architects make better decisions in the early phases of a project instead of adding expensive technology at the end.
  • Using the most recent climate science as a benchmark, it is safe to say there is no neutral in building performance today.
  • While we live in an era of resource scarcity, it is also a world of information abundance, allowing us to navigate solutions through research and data.


  • Simulation allows performance metrics to be woven into and inspire architectural solutions rather than exist solely as static data.
  • Simulation tests assumptions and helps the design team establish informed rules of thumb.
  • Owners and design teams can no longer rely on intuition and experience to solve increasingly complex and critical sustainable design problems--they need accurate and interactive data.


  • Begin with sustainable design questions, not software capabilities.
  • Create workflows using a suite of tools rather than looking for one silver bullet.
  • Successful incorporation requires an interdisciplinary team approach.


Radiation sky dome overlaid with sun path for a project in Buffalo, NY (above). When comparing it with the sun path at different times of year, the colors help designers understand which sun angles need to be blocked vs. which angles would be beneficial to allow solar heat gains.


In his book Design Energy Simulation for Architects, Kjell Anderson states that "The movement to reduce building energy use, which accounts for around 40 percent of global greenhouse gas emissions, will not be led by governments. If we succeed in reducing our energy use, it will be due to the passion of researchers, professionals and citizens who avoid both the cynic's easy perch and the willful ignorance of their impact."

This commitment to research has informed the planning of a number of recent projects. Using data from both the Department of Energy and projected Global Climate Models, we are able to simulate future scenarios to test massing, orientation and other building characteristics for best performance. By exploring future and current climate data in interactive ways, HGA's design teams can consider the effectiveness of passive strategies that would reduce energy consumption of the mechanical systems, focusing on passive cooling, heating and ventilation. These computational simulations provided verifiable data that allowed us to recommend tested strategies in the planning stage, enabling the building owner to move forward with greater confidence.


Simulation tools such Ladybug and Honeybee for Grasshopper and others are becoming invaluable to planning energy-efficient, resilient buildings. As simulation tools continue to be developed, building owners should consider the following in the planning process:

  • Use simulation technology to provide a data-driven process to test assumptions, reduce guesswork, and establish informed decisions.
  • Survey the range of environmental simulation tools available with your architectural team.
  • Define building performance questions as a way to choose appropriate simulation tools.
  • Assemble a simulation team with the right expertise to get accurate simulation results.

Topics: Sustainability & Resiliency