Prefabricated passive homes keep you comfy year-round with almost no energy

Taking two building techniques the United States isn’t very familiar with and using them together may sound like a bit of a gamble, but RPA and Ecocor have teamed up to do just that with their prefabricated passive houses.

More than 80 percent of homes in Sweden use prefabricated elements, but the numbers are much lower in the U.S. As for passive buildings, while the numbers in Europe are between 30,000 to 50,000, “We have about 350” here, Richard Pedranti, architect and founder of RPA, told Digital Trends. Yet he and Chris Corson of Ecocor think prefab passive homes are poised to catch on.

Passive homes reduce the amount of energy used by 80 to 90 percent, when compared to a typical house. Unlike a spooky old Victorian with mysterious drafts, these homes are built air-tight with triple-pane windows and two or three times the normal insulation. “It’s really a lot like making a big thermos,” said Pedranti. A fan with a built-in heat exchanger passes the heat energy from the stale outgoing air to the fresh incoming air, keeping the air streams separate. Passive homes are often thermostat-free, and use small heat pumps for any additional heating and cooling and for heating water.

RPA uses energy modeling tools to engineer a building’s envelope. Taking climate data from the building’s future location, the tool factors in annual heating and cooling, precipitation, wind, sun, and other environmental factors to determine how much insulation is needed. “Our energy modeling tools give us the ability to get very direct feedback about what happens when we change the configuration of the envelope and what happens to our consumption,” said Pedranti.

From the prefab side, rather than building an entire house on-site, much of the construction takes place in the factory. “We’re taking our designs and we’re using our digital information to create instructions for semi-automated factory equipment and this creates a lot of advantages,” said Pedranti. The digital instructions are fed to the saw, which then cuts the wood with no need to measure twice. Skilled craftsmen then do some of the assembly at the factory before the panels are sent by truck to the site. Once it arrives, the crew can have it put together in seven to 10 days.

RPA and Ecocor partnered a little under a year ago. They recently completed their first project, a 2,215-square-foot, four-bedroom home. Though it’s located in Albany, New York, the home’s interior should stay between 68 and 72 degrees Fahrenheit year-round.

“It’s shocking you can design a building like this and we’re not doing this,” said Pedranti. “Why would anybody not do it?”