Geothermal Heat Pump Case Study: Seattle Public Schools

Seattle Public Schools Lead on Clean, Green Heating and Cooling

When the Seattle Public Schools (SPS) facilities team floated the idea of switching from gas-fired boilers to geothermal heat pumps (GHPs) in 2004, they had no idea whether it would work. The only local use case that supported adopting the technology was an elementary school where a geothermal heat pump used for water storage had reduced the size requirements of a replacement boiler. 

Fast forward two decades. Now geothermal heat pumps are the gold standard of heating and cooling for all new and remodeled SPS school buildings, and the facilities staff are the unsung heroes of an energy-saving success story.

Conservation Drives Innovation 

The primary driver for transitioning to geothermal heat pumps was conservation, not regulation. When SPS retrofitted James Madison Middle School with the first geothermal heat pump system, renewable portfolio standards and energy conservation codes were not on most school districts’ radars.

“It was really the school district wanting to be a good steward of the environment versus anything we were required to do,” SPS Director of Facilities Operations Frank Griffin said. “SPS did it because we thought it was the right thing to do.”

As it turned out, being good stewards of the environment also benefited their bottom line.

Ahead of Code

All 15 remodeled or replaced schools in the district that have installed geothermal heat pumps have eliminated gas-fired boiler systems, along with their associated maintenance costs. At elementary schools, geothermal heat pumps have lowered the energy use intensity (EUI) from 42 to 15–20.

When comparing energy use across all buildings while accounting for weather variations, SPS has realized EUI reductions of 30%–77%, including when stepped-up ventilation increased electrical loads during the coronavirus pandemic.

“It was so successful right out of the gate, there really was no reason to look back,” said Mike Kennedy, the district’s mechanical, electrical, and plumbing coordinator for capital construction.

The Seattle 2018 Energy Code now requires all-electric buildings. The region also has two building performance standards coming online in 2026—a statewide Clean Building Performance Standard that designates target EUIs based on building types, and Seattle’s Building Emissions Performance Standard, which includes a carbon metric.

SPS was far ahead of the curve on all counts. All new SPS buildings are all-electric and their EUIs are far below state targets.

Good Stewardship Has Its Rewards

“SPS now designs all facilities with geothermal heat pumps as our first go-to system as we continue to modernize or replace our school buildings,” said Ian Brown, one of the district’s three resource conservation specialists tasked with managing utility costs through low-cost and no-cost operating strategies.

The shift to geothermal heat pumps was foundational to the ongoing success of their efforts to improve building performance and comfort while lowering resource use and maintenance costs, and schools have reaped the benefits in more ways than one. 

Five years ago, the SPS Resource Conservation team presented schools that achieved at least one conservation goal with Shared Savings Awards in any of three focus areas, including water, energy, and waste reduction. Eighty-three schools shared the combined awards of $47,400.

Benefits Increase With Technology Advances

SPS now aims to retrofit two to three schools per year, installing state-of-the art geothermal heat pump systems. Past systems have been funded by voter-approved property tax levies, but the district aims to tap into Inflation Reduction Act funding for future projects.

Those schools will also benefit from two decades of advances in geothermal heat pump technology.

“The coefficient of performance is greater on those [new] units, so we don’t need to extract as much heat out of the ground,” Griffin said. “So the utility costs will actually go down more, and we’ll have more energy put into the classroom.”

“Our first project was James Madison Middle School in 2006. Our desire was an efficient HVAC system that reduced energy consumption, was easy to maintain, and had great longevity. SPS now designs all our facilities with geothermal heat pumps as our first go-to system as we continue to modernize or replace our schools.”

Ian A. Brown, Resource Conservation Specialist, Seattle Public Schools

Contacts:

For questions about this case study, contact Ian A. Brown, IABrown@SeattleSchools.org.

For any website technical issues or general questions about geothermal heat pumps, contact DOE.Geothermal@ee.doe.gov.