Tapping into the constant temperature 1,200 feet underground, a Tribeca architect pioneers the use of geothermal technology to heat and cool his rock solid, energy efficient family home.
Yes, it’s big—especially by Manhattan standards, where closets often pose as bedrooms and bathtubs can be found in kitchens. And yes, it’s grand—although its owner, architect John Petrarca, has some sage advice about scoring designer finishes at bargain-basement prices.
But before you dismiss this five-story, 6,000-square-foot home and office space (4,000 square feet are for John and his family; 2,000 are for his five-person office) in New York’s historic Tribeca neighborhood as too big and too grand to be green, consider the innovation and imagination that went into lessening this urban infill project’s impact.
In the early 1980s, when Tribeca (short for Triangle Below Canal Street) was still an urban wasteland full of derelict, vacant buildings, John and his wife, Sarah Bartlett, bought a 1,600-square-foot, four-story house on Reade Street, which they renovated themselves. “We did all of the plumbing, heating, and carpentry ourselves,” John remembers. “And Sarah mixed about 100 bags of cement.”
The couple also bought the industrial loft building next door and, a few years later, the former butter factory next door to that. Eventually, he and Sarah sold the home they had renovated and went to work on a new home as well as four speculative townhouses. And in the process of developing his Reade Street empire, he’s also created what he calls “the greenest house in Manhattan”—a castle of sorts—for his family.
They chose limestone and oiled wood floors, low-toxic paints, natural linoleum, and natural wood finishes that wouldn’t outgas harmful chemicals.
Steel, foam and concrete
John, Sarah, and their two children, Ian and Emilia, live in the tallest building ever to be built using insulated concrete forms (ICFs)—and the first of its kind in the city. These structural forms, made of polystyrene foam insulation and concrete, were chosen for their superior insulation qualities as well as their thermal mass—which means significant energy savings compared with wood or steel-frame homes. John was also drawn to the material because he could attach the wood and Sheetrock walls directly to the Styrofoam, leaving no air space or cavities, which contributes to their superior insulation and, perhaps just as important in New York, harbors no roaches or rats.
Pioneering the use of this material in an urban setting was no small task. “There’d been no history of its use here,” says John, adding that he and city building officials “argued and argued and argued” about the building material. The city eventually sued John, but he won the right to use it.
His next hurdle was dealing with the labor unions, who couldn’t agree on whose jurisdiction ICFs would fall under. Who should be in charge here? Masons, concrete workers, carpenters? The carpenters won out; concrete workers assisted.
ICF blocks are lightweight and waterproof, which meant John’s crew could work right through a snowy winter. Once concrete is poured into the forms, they become a solid, monolithic mass. “We live in a bomb shelter here,” says John—and that proved to be important in September 2001, as the house is blocks from the World Trade Center site. The towers’ collapse measured 3.0 on the Richter scale in lower Manhattan, but John and his family didn’t feel a thing.
In the front of the building, a facade of recycled steel—chosen to reflect the historic cast iron buildings of the lower Manhattan neighborhood—was placed over the ICF superstructure. The twenty-five-foot by sixty-two-foot facade, fabricated in a Newark, New Jersey, bridge factory, weighs nineteen tons and had to be delivered in twenty-five-foot chunks, then welded together on the site and lifted into place in one piece. “It was like a barn-raising,” John says, remembering all the neighbors who turned out to watch the spectacle.
Tapping into the eEarth
Perhaps the home’s most astonishing feature is the way it’s heated and cooled: through a geothermal heat pump, a system of underground pipes that uses the earth as a heat sink in the summer and a heat source in the winter. The U.S. Environmental Protection Agency (EPA) has declared geothermal the most energy efficient, environmentally clean, and cost-effective space conditioning system available. For John, it just made good sense.
“We’d made it over the financial hurdle of buying a house,” he says. “But we couldn’t pull it off if the house were expensive to operate. We had to layer in the potential energy costs.”
Geothermal systems—which John considers one of the only cost-effective energy choices for smaller buildings in a dense urban area—save energy (which sells for nineteen cents per kilowatt in New York) by moving hot and cold rather than creating it, as traditional heating and cooling systems do. In New York, the earth’s internal temperature remains at a relatively constant fifty-two degrees. So in winter, pipes full of liquid reach deep underground to pull heat up via heat pumps into the building; the heat is then distributed through a radiant floor system and fan-coil units. In summer, heat from the building is then discharged via heat pumps back into the cooler ground.
In addition, a desuperheater transfers the excess heat from the heat pump’s compressor into the hot water tank. In summer, hot water is free; in winter, water heating costs are cut nearly in half.
John first discovered geothermal while working on a high-end penthouse for a client. He didn’t want to install an air conditioner because it was big and noisy, and accommodating it would mean reducing the penthouse’s size. Geothermal equipment can be kept in a basement—relatively unusable space. “But at the last minute, the developer said, ‘I’m a smart New York developer, and no one’s ever done this before. I’m not doing it. I’m not going to be the first,’” John says. And he realized that if he wanted to tinker with this technology, he’d have to try it on his own home first.
Again, no small task. John had to apply for and receive approval for an oil and gas well before he could drill the eight-inch hole for his pipes. This attracted the attention of the EPA, which actually proved to be a blessing. That agency enthusiastically supported John’s experiment and pushed through the application to get his wells approved.
A drilling rig with specialized steerable bits bored through 100 feet of dirt, then 1,100 feet of Manhattan schist before it hit its mark. “This was a rig that was meant to be used in the country, and it was very, very noisy,” says John, who had to endure his neighbors’ wrath during the twenty-eight days it took to drill a well for each of the five houses.
Inside the house, John and Sarah chose limestone and oiled wood floors, low-toxic paints, natural linoleum, and natural wood finishes that wouldn’t outgas harmful chemicals. Still, they were concerned about sealing their family inside a super-insulated, super-tight home, which can lead to health problems. So John installed a balanced ventilation system that provides an unusually high level of filtration and fresh air, free of pollen, mold, and particulates.
Again, this proved particularly beneficial in late 2001, as a lethal mix of dust, chemicals, and asbestos from the WTC towers blanketed Tribeca. John and his family closed all the windows tight and changed the filters weekly. “Only a minimal amount of dust got into the house, even though it was inches deep outside,” John says.
September 11 also delivered a bizarre twist to the list of green features in John and Sarah’s home. The house faces south, giving it a natural orientation to take advantage of passive solar—collecting the sun’s warmth in the thermal mass of the limestone floor during the day and releasing it back into the space at night. The quality and quantity of light inside the home changed drastically on that tragic day. Sun now floods the main living spaces from morning until late afternoon. And because the radiant floor system circulates throughout the house, that solar gain can be collected and distributed, even to rooms with northern exposure.
“While the remaining World Trade Center environmental dust and debris keeps us inside and makes our windows hard to keep clean, the loss of the towers has allowed more winter sun to flood into the house, making sitting at the dining room table an even more wonderful experience,” John says. “I do not think we would have traded tragedy for sun, but I think both will be with us here in lower Manhattan for a long time.”
Tricks of the trade
The house is technologically savvy and chic, yet it also envelops and nurtures the young family. Much of this is because of the natural finishes John and Sarah chose—and they were able to afford many of these largely because of John’s persistence. As an architect, he is constantly exposed to high-end goods, yet he built his home on a budget.
When he fell in love with door handles made by an Italian manufacturer, he called the company and learned that it had several “rejects” available because of manufacturing problems. He negotiated a deal with Bulthaup on the kitchen, using black Marmoleum flooring on the face of the cabinets; he was one of the first designers in the United States to use it.
He learned that Toto, which makes high-end low-flush toilets, needed a New York City installation to garner city building inspectors’ approval, so he took the risk—and a deep discount. He scored again with Fine Paints of Europe, a European maker of highly pigmented, low-toxic acrylic paint. “I cajoled the company into giving us the paint at a significant discount because of the uniqueness of the project,” he says.
In several cases, John simply found cheaper—though just as luxurious—alternatives to high-end products. The shower door in the master bathroom is simply an etched glass closet door fitted with rubber gaskets; the alternative, a solid glass shower door, was twice as much.
The stair treads on the seven-story staircase are made of inch-thick slabs of recycled glass, which was cheaper than concrete or stone. The handrail for the seven-story central stair was very costly, so John slid a large piece of stainless steel mesh used in filtration plants between the stairs. “It’s like woven tapestry, but out of steel,” he says.
And the result? “I feel blessed to have so much space and light in the city,” John concludes. “The kids have really enjoyed the vertical nature of the house—it’s great for hide and seek—and I have found it a wonderful laboratory for future developments.”
Sit in on dozens of practical workshops from the leading authorities on natural health, organic gardening, real food and more!LEARN MORE