Energy Modeling Yields Critical Building Design Information and Increases Potential Cost Savings

This is the third in a series of posts expanding on our 2026 State of Sustainability.

Perkins Eastman embarked on a 10-year project in 2020 to increase energy modeling and significantly reduce the energy use of our built work to meet the AIA 2030 Commitment’s net-zero emissions goal. Today, we are running energy models for all new projects. In 2025, our firm saw a 60-percent average predicted energy use reduction against the Commercial Building Energy Consumption Survey baseline, improved from 49 percent in 2023, the year before energy modeling became a firmwide requirement.

Sustainability specialists Ryan Dirks and Juan Guarin, who work across our 18 practice areas, discuss the many benefits of incorporating energy modeling into our process.

Juan Guarin: For the first time, our projects are performing better than the industry average predicted energy reduction, but we have a long way to go.

Ryan Dirks: We are making meaningful progress, and, in the process, we are building institutional knowledge of energy-saving strategies that actually move the needle.

Energy models test for factors such as building orientation, insulation thickness, and mechanical system design. Certain variables may lead to an improvement in cooling, heating, and overall energy use, but in some cases, improvements in one category (green) are canceled out by increased energy expenditure in another (red). All graphics © Perkins Eastman

Guarin: Can you share some of the instructive things we have learned from these modeling exercises?

Dirks: For certain project types, adding more wall insulation makes a big difference. For others, it makes no difference or may even have a negative impact. At Alexandria City High School, for instance, we were going to increase the insulation to the exterior walls to try to achieve net-zero goals. The energy model showed that it increased cooling loads more than it reduced heating, so it wasn’t a good use of the client’s money.

Alexandria City High School solar radiation analysis identifies window-to-wall ratio guidelines.

Guarin: Boston Arts Academy is another good example of the performance versus cost assessment. Triple-pane glazing was going to cost more money, but the energy model showed that it could reduce heating and cooling needs significantly over double-pane glazing. The upfront investment savings we achieved with a smaller mechanical system more than offset the cost of the higher-performing envelope.

At Boston Arts Academy, the choice of triple-pane glazing lead to reduced mechanical system expenditures and long-term utility bill savings. Exterior photograph © Robert Benson Photography

Guarin: Calculating embodied carbon—the energy expended during the extraction, manufacture, and transportation of the materials for our buildings—is another piece of the pie.

Dirks: Embodied carbon represents roughly half the carbon footprint of the built work we produce, and this number can be even higher for high-performing buildings that use very little energy. We need to look at operational and embodied carbon as a holistic picture.

For the new computer science laboratories at the University of Massachusetts Amherst Manning College of Information and Computer Science, we modeled a hypothetical steel structure to study its carbon footprint versus timber. We found that using mass timber saved roughly 55 to 60 percent of the total embodied carbon footprint of the project. In this case, it was a fairly cost-neutral decision.

For the computer science laboratories at UMass Amherst, embodied carbon models comparing the global warming potential of a steel and concrete structure versus one employing mass timber showed a dramatic decrease.

Guarin: In an ideal world, all our projects would be mass timber structures, but we are not there yet. So, we are thinking about alternative strategies. For example, multiple techniques can make a concrete structure more sustainable. We can substitute a portion of the cement mix, an ingredient of concrete, with alternatives such as fly ash and slag, which are byproducts of coal production and steel manufacturing. Typically, these choices are cost neutral.

Dirks: We can also reduce the total number of materials we use in a project. This can save embodied carbon as well as cost.

Guarin: The most sustainable material is the one we don’t use.

Dirks: In a recent tenant-improvement fit out, we quantified the number of gypsum partitions and floor finishes that we did not specify compared to a typical project. It was about a 40-percent reduction overall in the space’s embodied-carbon footprint.

Dirks: Depending on the building type, architectural strategies can have different levels of impact on the reduction of energy consumption. What other strategies can be used to achieve a sustainable building?

Guarin: True. Certain buildings consume more energy than others. Healthcare is one of them. Apartment buildings and student dorms use significantly more hot water than other building types. In these cases, we focus on aspects like glare, daylight, and thermal comfort—not solely on the energy piece—that impact users.

Dirks: Deploying an energy monitoring service to review a client’s energy bills after project completion is another way we can impact energy usage and costs. It has helped us validate what is working, and in some cases, it has helped us troubleshoot problems that have saved clients significant money on building operations that may otherwise have gone unnoticed.

Guarin: Our modeling and monitoring efforts are critically important, but there is more to good sustainable design than energy.

Dirks: We always factor in the wellness of people and planet to ensure we are not making isolated decisions. Our design process helps us verify that our choices are having a positive impact, and it helps us find holistic balance in our design decisions on every project.

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