Two years ago, on a tree-lined street in Princeton, N.J., a truck-mounted drill arrived at a modest two-story home. Its goal? To dig a 500-foot hole in the front yard.
Although the contraption resembled an oil rig, it would be prospecting for a cleaner energy source: water. Forrest Meggers, an engineering and architecture professor at Princeton University, was installing a geothermal heating and cooling system for his house, which he was also gut-renovating to be a showcase for green living.
Dr. Meggers, 43, who teaches a course called “Designing Sustainable Systems,” is not your average D.I.Y.-er. Though he speaks with the drawl of a surfer and lives in what is starting to look like a gingerbread house, he is all business when it comes to lowering greenhouse emissions as society stubbornly clings to fossil fuels.
“We’re basically driving with our seatbelts off at 100 miles an hour right now,” he said.
With his curious neighbors looking on, he is making his house a live-in laboratory. The ongoing construction, which began three years ago, has tested the patience of his family of six. But when the home is also a real-time model for fighting climate change, the risks and rewards can multiply, and the projects can seem endless.
The renovation has gone $40,000 over its $300,000 budget so far. For a year, the professor and his wife, Georgette Stern, also 43, had to move their bedroom and makeshift kitchen to the basement, where Ms. Stern cooked for the family using a hot plate and a slow cooker. “It was rough,” she said.
“Forrest is a little bit non-compromising with his ideals,” said Ms. Stern, who got her engineering Ph.D. along with her husband, but left academia when the couple’s first of four daughters was born. “He pushes you beyond what you thought was possible,” she continued. “But sometimes I have to draw a line.”
As an undergraduate at the University of Iowa studying mechanical engineering, Dr. Meggers originally wanted to design bicycles for environmental reasons, he said. But then he learned more about the effects of climate change. “I realized, ‘Oh, my god, buildings are terrible,’” he said. Gradually, he switched his focus to architecture and engineering.
At his lab at Princeton, called C.H.A.O.S., which stands for Cooling and Heating for Architecturally Optimized Systems, Dr. Meggers and his students are developing heating and cooling techniques that he often tests at home. A self-taught builder, the professor has incorporated both cutting-edge technology as well as more traditional conservation methods.
Geothermal, a centuries-old technique to harness energy that is experiencing a resurgence across the country (including on college campuses like Princeton), was just the beginning for him.
There are various ways of using geothermal energy, but Dr. Meggers’s system taps into deep underground water that retains a constant temperature of about 50 degrees. Then, a heat pump distributes the water through the home via a network of pipes under the floor, in what is known as a radiant heating system. (In the summer, the heat pump can be reversed to extract heat from the house, keeping it cool.)
Other aspects of the project have centered on maximizing the space of the family’s house without making it bigger. The concept is important to the professor, who eschews hulking American homes and their elevated energy demands. But it was the practicality of the plan that appealed to Ms. Stern. “We have four kids and a small house,” she said.
Now, each daughter — ranging in age from 9 to 13 — has her own room on what used to be a cramped, two-bedroom second floor. The demolition of the upstairs involved a new roof and floors, under which Dr. Meggers installed the pipes for the radiant system. This allowed air ducts to be removed, opening up more space and making way for the girls’ private bedrooms.
The floors covering the pipes are reclaimed wood from ash trees killed by invasive insects. There is also a bedroom door made from a local red oak that had to be cut down, insulation courtesy of sheep’s wool from the professor’s family farm in Iowa and a sink atop a toilet that reroutes water from washing hands to flushing.
There are other green houses in Princeton, said Abel Smith, a local sustainable builder who has helped with the renovation and co-organizes annual tours of the homes. But the Meggers house “is a standout,” Mr. Smith added, because it is so comprehensive in its sustainability features. “He did it all,” Mr. Smith said.
But it hasn’t all gone smoothly. Ms. Stern had to tap the brakes on her husband’s seemingly boundless energy when he turned to the kitchen. “This made me crazy, since I’m the one who cooks,” Ms. Stern said. And when Dr. Meggers insisted on pricey cedar shakes for the roof, Ms. Stern negotiated a compromise. They ended up putting cedar on the dormers and asphalt everywhere else. Asphalt shingles are cheaper but not as environmentally friendly.
The family has also questioned the professor’s cooling system, which depends on cold water under the floors, monitored by sensors that keep the sub-floor temperature above the dew point, when condensation occurs. But during a New Jersey summer, the dew point can exceed 70 degrees, which means the floors can grow warm.
“I know he’s trying to make our house more eco-friendly and stuff,” said one of the twin daughters, Maelin Meggers, 11, on a balmy day in October. “But it’s not as cold as other houses.” In the interest of keeping his wife and daughters happy, Dr. Meggers has built a system of coils and fans that cool the air on sweltering days.
The exterior of the home incorporates another design element that allows for natural heating and cooling: passive solar shading. On the south side of the house, Dr. Meggers built hooded windows. A low winter sun hits beneath the ledge to warm the house while the high summer sun hits the ledge, which shades the home.
“It’s what people have been doing since the Anasazi Cliff dwellers built their caves on the sides of the mountain,” Dr. Meggers said.
The to-do list for the house includes solar panel installation. Once that is complete and the home goes off the grid, two 530-gallon “water bladders,” an unconventional spin on thermal storage tanks, will reduce the need for battery power. These small, malleable bags, which are stuffed into a crawl space in the basement, allow for heating and cooling to be distributed without the electrically-intensive heat pump.
More esoteric projects, which are being developed in the C.H.A.O.S. lab, include fine-tuning the zoned sensors and trying out different desiccants to take humidity out of the home. Both initiatives contribute to cooling a house without air-conditioning, which Dr. Meggers described as a wasteful process.
“I’ll be done as soon as I stop having ideas,” Dr. Meggers said. But the house is already a home, he added, especially since the daughters have their own rooms and there are working bathrooms and a kitchen.
Earlier this year, a mechanical engineering class from Princeton visited the house. Helena Frudit, a senior, was impressed with how much sustainable work had been completed on a street so close to town, as opposed to “off the grid in the middle of nowhere,” she said.
“He showed us that you don’t have to be in the middle of the forest to have a cleaner house,” she said.
