In downtown Boise, the sidewalks aren’t just warm with summer heat — they’re literally powered by it. Beneath the Idaho Capitol, a massive underground hot spring fuels the nation’s oldest and largest geothermal heating system, The Arbiter reported.
Unlike most geothermal systems in the U.S., Boise’s taps directly into natural hot water from the earth, a rarity in American cities.
“Our geothermal system is essentially tapping into a hot spring that sits under Boise — and that’s unique,” Amy Parrish, sustainability director at Boise State University, told The Arbiter. “It’s not something that a lot of communities have access to.”…