Mankato-based company builds underground houses for buyers seeking durability, energy efficiency

Growing up, Pete Bissonette always wanted to live in a bus or a cave.

The latter dream came true, at least in a sense.

Bissonette has one of the about 650 homes Mankato-based Earth Sheltered Technology has built since it began in 1981. The company, which has houses in the Twin Cities and Wisconsin as well as in California and Alaska, specializes in partly underground structures, basically man-made caves.

Underground homes, also known as Earth-sheltered homes, have been around for nearly as long as humans have, though the modern incarnation seemed to gain traction in the 1970s after the 1973 oil embargo and ensuing energy crisis, according to an article in magazine Mother Earth News. At the time, people were looking to reduce energy usage, especially when it came to heating and cooling their homes.

Underground homes have other benefits too, including durability — particularly in the face of natural disasters like tornadoes — and low-maintenance needs (no need to paint when dirt and grass covers the whole house). Perhaps that’s why Earth Sheltered Technology has produced the bulk of its homes, about 450, in the past 17 years, said owner Jeff Hickok.

Besides achieving his childhood dream, Bissonette’s other inspiration for building his underground home was the book “Earth Sheltered Housing Design,” published in the late 1970s by the University of Minnesota’s Underground Space Center. John Carmody, one of the leaders of the underground home movement at the time as a systems designer and environmentalist, oversaw the center and the book, which sold 250,000 copies, according the to University’s website.

“I loved every bit of building it,” Bissonette said of his Shakopee house. “I’m glad I made the decision to build it. I have no intention of ever selling it and made it wheelchair accessible so I can get around in case I need one.”

Bissonette, who grew up on the Iron Range said he has long worried about tornadoes. An underground home, he thought, would protect against that.

Underground homes are known for their durability, Hickok said. He said at least two tornadoes have gone over his Mankato underground home. It’s a reason his company has been building so many underground houses in Oklahoma and Texas. Texas averages about 140 tornadoes each year, the most of any state, while Oklahoma ranks in the top five, per CNN.

Other clients have reported the structures being able to withstand earthquakes, Hickok said. The U.S. Department of Energy’s website said Earth-sheltered homes can cost less to insure, as they naturally can withstand high winds, hailstorms, tornadoes and hurricanes. The Australian Broadcasting Company even published a story last year about such homes gaining popularity because of their ability to withstand hot temperatures and bush fires.

“The earth is a very good protector for tornadoes,” Hickok said. “A tornado can’t damage a home unless it can completely surround it, and with most underground homes, they only have south-facing windows.”

In addition to saving money on a homeowner’s insurance policy, an underground home could also save on claims. Hail, for example, does minimal damage to the roof, with only some of the piping up top sustaining damage.

Earth Sheltered Technology was a retirement job for Jeff Hickok’s father, Jerry Hickok. Jeff Hickok said his dad had a fascination with living in a cellar as a child and created the company after finishing at his corporate job.

As a kid, Hickok dreaded going to home shows with his father and didn’t pursue the business until later in his life, taking it on around 2007.

“I didn’t realize how forward-thinking dad really was with energy-saving and safety of these things,” he said. “I’m so proud to be running the company that my father pioneered.”

Another big selling point: Underground homes use about 80% less energy than a traditional home of its size. That’s because the ground insulates it to keep it at a stable 50-60 degree internal temperature. South-facing windows warm it during the day, Hickok said.

Dick and Jeanne Newport of Berlin, Wis., remember the 70s energy crisis and how people wanted to be energy independent. They visited a friend’s underground home back then and left inspired to have their own one day, which eventually happened in 2016.

Their two-bedroom, two-bathroom underground home is about a 4 ½-hour drive from the Twin Cities. About 980,000 pounds of solid concrete surrounds it, and, most winters, only a single wood-burning stove heats the 2,000-square-foot property, Dick Newport said. On the roof, the two have planted native grasses.

“People thought our house was a septic mound because they didn’t know what it was,” Jeanne Newport said. “Until you get to the front, you can’t tell it’s a house. There’s tall prairie grass all around it, and it’s really hard to see the whole rounded shape.”

They estimate they pay about $115 in utilities for their highest usage month. The average Minnesotan pays more than $151 a month for electric and gas utilities, according to Kris Lindahl Real Estate.

The Newports estimated it cost about $350,000 to build their house including all the interior design, electrical and plumbing. When adjusting for inflation, that comes out to $465,799 in 2024, more than the current median price of homes in the Twin Cities, $380,0000. Earth Sheltered Technology builds several concrete dome structures with steel beams as support, insulating and waterproofing them for the price of about $150 per square foot, according to Hickok. But the rest is up to the homeowners to DIY or hire contractors.

Having to do extra work didn’t bug the Newports, and the lower energy bills every month makes up for the cost of building the home.

“There’s not a lot of maintenance because most of the house is covered in dirt, and it’s quiet if the windows are closed,” Dick Newport said. “We have peace of mind living here.”

This past summer, a “hobbit house” in Pine Lake Township listed for about $180,000, drawing attention for its unique underground design.

Being different is yet another perk of having an earth-sheltered home for Bissonette, who is working on an art piece made of 5,000 empty wine bottles.

Outside of his two-bedroom, two-bathroom, 4,000-square-foot home, there’s a large labyrinth in his yard filled with statues from Bali, including one that can identify evil, Bissonette said. There’s also tall native grasses growing on the roof among a smattering of solar tubes and ventilation pipes. His home blends into the surrounding vegetation looks like several hills with trees and shrubs growing on them.

It’s not until visitors turn a corner that they’re able to see two garage doors poking out, alongside a front door, wide driveway and windows. When he built his house in 2001, many of his neighbors thought it looked like a military base because of how hidden it was from the main road.

But the rooftop patio makes it perfect for hosting, Bissonette said of the views of rolling farmland and acres of wildlife. Bissonette taught himself and installed much of the electrical work, also repurposing salvaged wood for the interior walls, making it uniquely his own.

“What surprises people the most is how light it is in the house,” he said. “They expect it to be dark because it is underground, but the curved interior surface of the domes reflect light throughout the space, bouncing it across the inner surfaces, making it bright and light-filled.”