March 20, 2015
by Kathy Zhao
Correction: The type of insulation De Barbaro will be using in her duplex is "rock wool." In the story we mistakenly referred to it as "rock wall."
It’s starting to feel like spring outside, and Lucy De Barbaro is probably more excited than most people for the warm weather. She’s been waiting all winter for her new house to be built.
De Barbaro, who’s Polish, and her German husband, aren’t building a typical American home. She says that's because they won't have to deal with pesky indoor drafts creeping in during the colder months.
"I would feel impotent if I lived in my home and all the energy that I’m pumping into it was like escaping, escaping, escaping," she says.
De Barbaro lives in an apartment, but she says she can imagine how frustrating it must be for people who are spending a lot of money on heating.
She says "it's their money leaving their homes, escaping through the windows and cracks."
De Barbaro says her new duplex will be "super-insulated," meaning that the insulation in her walls will be twice as thick as in an avrage home.
She and her husband have decided to use something called "rock wall," a type of board made from industrial waste. According to De Barbaro, this waste is actually good for maintaining the temperature and keeping moisture out of the walls—moisture that naturally occurs when it rains or snows.
The couple are making all kinds of calculations regarding the construction of their new home.
"We account for all the shadows that fall on the house, we account for energy loss in the corners and around window openings," she says. "Every material is modeled and predicted for in the building."
Those calculations help them save money on heating—one of the most costly parts of owning a home in the northeast. However, money isn’t their only motivator. Their primary goal is drastic reduction in the amount of energy their house will use every day.
De Barbaro says that Passive House is the most stringent energy building requirement in the world.
"So rather than add energy let’s say from geothermal or solar to address the house energy needs, the first principle is to reduce the amount of energy needed by the house," she says.
For a house to be certified as “passive” it has to meet limits on how much energy is used for heating and cooling. These limits also apply for appliances people use regularly, like the fridge, clothes dryer, and hot water tank.
De Barbaro says a key qualification of Passive House certification is that it's performance-based, not points-based like LEED.
LEED is more well known in the U.S. as an energy efficient building standard than passive certification. In LEED, builders rack up points for green construction practices—like using recycled materials, or adding solar panels.
De Barbaro says that LEED is more focused on how a house is built, whereas Passive House is more concerned with how it functions.
"In LEED, the points gained don’t translate into energy savings," she says.
Meanwhile, a Passive House has to show that it saves energy by passing tests before, during, and after construction. One of these tests measures airtightness. The house is filled with pressurized air. If it holds that pressure for a few hours, without leaking, then it can be certified as passive.
De Barbaro says a Passive House is like a thermos.
"It’s the idea of rather than keep adding heat you should sort of retain it and take advantage of doing much more incremental tiny addition to the heating," she says.
When she says tiny, she really means it. Her heat pump will run on only 1800 watts of power—about the same as an average hairdryer.
De Barbaro says their house will also be equipped with the most efficient Energy Star appliances. Her hot water tank will be only 2 gallons, rather than the typical 80. Plus, all of the lights in her home will be LEDs.
She says if they have money left over after the main construction is completed, they'll even add some solar panels to the roof to provide another source of energy.
However, these unique construction materials and efficient appliances also make it more expensive to build than an average American home. De Barbaro says people always ask her when she expects to see a return on her investments, but her concern isn't just about economics.
"Do you only reach for things that are a return on investment? No, you reach for things that are of value to you," she says. "For us this is a value, we want to pay more because we believe this has implications for the environment."
De Barbaro and her husband hope to move into their new, passive home this summer.
Photo of De Barbaro, architect Erik Fritzberg, and contractor Barry O'Block by Kathy Zhao.