Boise will heat 300 affordable homes with 177-degree water from underground

Boise plans to run a 177-degree-Fahrenheit geothermal loop into a new affordable housing development with more than 300 homes, and the city says the connection could cut residents’ utility bills by as much as 80%. The project sits in the Lusk District and carries a price tag of about $140 million, according to the city.

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Groundbreaking is expected in spring 2027, with the first residents moving in during 2028. Until then the plan remains a funded intention and not a set of finished buildings, and the schedule depends on financing pieces that the city describes as still coming together.

Canary Media’s Alison F. Takemura reported on Nov. 2 that the project would extend what the outlet calls the largest geothermal heating system in the country. Her article describes pipes carrying naturally warmed water from underground to about 100 buildings, including the Idaho State Capitol. The city says the network already cuts thousands of tons of carbon emissions each year, equal to taking more than 2,000 gasoline-powered cars off the road, and Boise has set a goal of carbon neutrality by 2050.

The Lusk District project and its $2.5 million gap payment

The housing is a planned multifamily development in the Lusk District, built by J. Fisher Companies in partnership with the city’s Housing Land Trust Program. Boise’s Oct. 27 announcement says Micron Technology gave $2.5 million in gap funding, and that 10 percent of the homes are reserved for people leaving homelessness.

The city calls the effort the first by a U.S. city to use geothermal heat for multifamily affordable housing. Jake Wood, managing director of affordable housing development at J. Fisher Companies, said no other U.S. city has tried it.

Financing comes from several places, which is typical for affordable housing built with public land and tax credits. Idaho Housing and Finance Association tax credits and private activity bonds are part of the package, along with investments from the city, the Capital City Development Corporation and J. Fisher. The gift from Micron, the Boise-headquartered chip maker, filled a remaining hole in the money needed to extend the geothermal pipes.

Bloomberg Philanthropies money and the cooling question

In February 2026, the Bloomberg Philanthropies Mayors Challenge awarded Boise $1 million to upgrade the network for affordable housing and explore cooling uses, as the city’s release on the award explains. Maria Ortega, the city’s communications senior manager, said, according to Canary Media, that early-stage technologies could potentially use the system’s hot water for cooling, a use that would matter in Idaho summers.

April Arnzen, Micron’s executive vice president and chief people officer and president of the Micron Foundation, tied the investment to community support, noting that Boise has been the company’s headquarters for 48 years. Mayor Lauren McLean said the gift brings the city one step closer to delivering clean geothermal heat to hundreds of affordable homes.

District heating from a single underground source

A geothermal network of this kind circulates hot water through buried pipes to many buildings and not a boiler in each one. Boise’s own geothermal utility page describes the public works system, and the district’s heat comes from underground water that is naturally warm when it reaches the surface.

Because the heat source needs no fuel purchase, the city argues that residents could save up to 80% on utility bills. That figure is a city estimate for the new homes and not a measured result, since no building in the Lusk development exists yet. The Housing Land Trust model and the redevelopment details are laid out on the city’s Lusk District page.

Boise is not alone. The Building Decarbonization Coalition tracks 33 geothermal network projects that are planned, under construction or finished across the country, and its neighborhood-scale project map lists them. Framingham, Massachusetts, has about 140 customers on an Eversource-owned network, the first utility-owned one in the U.S., and an $8.6 million federal grant announced last December is meant to double its size. Denver and Enfield, North Carolina, are also planning systems.

The project also carries a policy test. Heating is a recurring cost that falls hardest on lower-income households, and the city’s 80% estimate is aimed squarely at that cost. Two outside grants, $1 million from Bloomberg Philanthropies in February and $2.5 million from Micron in October, arrived within nine months of each other, which suggests the funding gap was closed in steps and not in one commitment. The city’s release describes the Micron money as gap funding for the Lusk Housing District, so the remaining budget still leans on tax credits, bonds and local investment. The open question is whether the 80% savings estimate holds once residents move in during 2028. The city has published the figure but not the rate structure or the assumptions behind it, and the first winter of bills will be the real test.

This article was produced with the assistance of AI and reviewed by Morning Overview editors prior to publication.

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