Get Low-Tech Efficiency with 'Passive House'

It Even Makes Sense for Schools and Healthcare Facilities

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Michael Knezovich is director of communications at Passive House Institute US.

Julie Torres Moskovitz is author of "The Greenest Home: Superinsulated and Passive House Design."

Darren Macri is founder of BleuNest.

Stan Salwocki is manager of Architecture and Engineering, PHFA.

Posted: Wednesday, June 17, 2015 3:38 pm

Passive house is a construction concept that aims to create energy efficient, ecological, comfortable and affordable housing – basically a modern home using a minimal amount of energy.

Rather than gaining energy efficiency through high-tech systems, passive houses rely on thicker insulation, high-performance windows and air-tight construction.

For decades, the passive house concept has been written off as too risky, too complicated, too expensive and downright goofy. But with cities like New York City, releasing ambitious green initiatives that aim to reduce carbon emissions significantly by 2050, passive house is gaining traction as a pathway to net zero housing.

"Passive house is a house built to be extremely efficient," said Michael Knezovich, director of Communications at Passive House Institute US (PHIUS). “You can sit by a window in the winter and not feel cold air.”

PHIUS, located in Illinois, is a nonprofit organization “committed to making high-performance passive building principles the mainstream best building practice, and the mainstream market energy performance standard.”

The organization has trained more than 1,700 architects, engineers, energy consultants, energy raters and builders. It also is the leading certifier of passive buildings, with more than 120 single and multifamily projects certified and still more in the pipeline, according to the PHIUS.

When Knezovich describes passive house, he explains that these buildings, including schools, healthcare facilities and multi-family units, are very comfortable and resilient. They are very quiet (you wouldn’t be able to hear your neighbor’s dog barking) and they lack active heating and cooling systems.

Passive houses have very good air quality due to a mechanical ventilation system that continuously exchanges the indoor or stale air with fresh outdoor air. It doesn’t recirculate air. In a 2013 New York Times article, “The Passive House: Sealed for Freshness”, a reporter described the air inside a Seattle passive house as so fresh “you can almost taste its sweetness.”

Passive building is typically designed to maximize solar gain and there is very little conductive loss, Knezovich said.

Yet, despite all the green aspects of passive building that make it attractive to environmentalists, it can also be constructed to appeal to those living in an historic neighborhood.

“In some circles, people believe that conservation means a sacrifice in some way and that leads to a house that only a 'tree hugger' would want to build,” Knezovich said.

But as Julie Torres Moskovitz illustrated in her book, “The Greenest Home: Superinsulated and Passive House Design,” passive house doesn’t equal ugly sugar cube house. The book examines 18 innovative passive houses and their case studies. One of those houses, a retrofit brownstone named Tighthouse, was designed by Torres Moskovitz. Tighthouse was the first certified passive house in New York City and it won a 2014 International Passive House Award.

Torres Moskovitz is the principal architect of Fete Nature Architecture, a “collaborative architecture firm whose process is founded in research and investigation of new ways to inhabit the urban fabric,” according to the firm’s website.

Torres Moskovitz said she is optimistic that the U.S. will follow the EU model and that cities like New York City will commit to nearly zero energy buildings, which follow the passive house example.

“The principles of passive house is the pathway to a life without fossil fuels,” Torres Moskovitz said.

She is encouraged by New York Mayor Bill de Blasio’s Built to Last/One City report, which describes a number of green-building initiatives, including passive house (see Page 36 of the report). Mayor de Blasio has a target of a 30 percent reduction in greenhouse gas emissions (below 2005 levels) by 2030 and an 80 percent reduction by 2050. Buildings are responsible for 75 percent of carbon emissions in New York City and the mayor’s office found that residential buildings account for 37 percent of the city’s emissions.

“I am noticing a push-pull play between the people and the government moving in the direction of sustainability,” Torres Moskovitz said. "I think cities like New York City, Portland, Seattle and Vancouver will lead the pack and the rest of the country will follow."

She said passive house makes sense for everyone, but especially for those in the affordable housing market. “This could make a gigantic difference in the lower class or even middle class,” she said.

Earlier this year, Pennsylvania became the first state to offer tax credits for low income passive house building.

The Pennsylvania Housing Finance Agency (PHFA) has been pushing energy efficiency when reviewing project applications for more than 10 years, said Stan Salwocki, manager of Architecture and Engineering at PHFA.

“We wanted to push the envelope a little further,” Salwocki said.

Applications submitted are scored and ranked in accordance with a numerical criteria. For example, developers may be awarded up to 10 points for the adaptive reuse of a vacant building and up to 30 points for developments located in areas with high poverty rates. This year’s applicants were also awarded up to 10 points for projects that met national or international passive house certification requirements. Passive house certification from PHIUS or the Passive House Academy is not required.

In February, PFHA received 130 applications for low-income projects. Salwocki said 37 percent were certified to passive house standards and eight were awarded the first passive house tax credits in Pennsylvania. Two of those are single family homes; the remainder are multi-family projects and townhouses. The projects are located throughout the state.

When it was announced that they would include passive house in the application criteria, there was a bit of push-back from developers, Salwocki said. The concern was additional costs associated with the specialized construction. But after reviewing this year’s applications, Salwocki said those concerns have evaporated.

“If you look at the passive house projects, they are interspersed within the range of costs of projects. They are not all on the high end. If you look at the costs... there is nothing that jumps out at me that says 'passive house,'" Salwocki said.

Darren Macri, founder of BleuNest, is currently building the first passive house in New Jersey. His family is hoping to move in this August and he is using his house to showcase passive house construction. Macri agreed there is a “minimal cost up-charge for this kind of building,” but over the lifetime of the building, people who live in a passive house will save more money than those who live in conventional housing.

“You are getting a better built home for a small premium,” Macri said.

Macri believes the more people who see and feel the passive house benefits to the environment, their health, their wallet and their own comfort, the more customers will be demanding passive houses. His goal is that passive house won’t be limited to wealthy environmentalists who can afford to build them. Macri wants to see the passive house model become the standard for every new home in the U.S.

“This is absolutely the answer. We all have to build this way,” Macri said.

PHIUS estimates passive house construction costs are 5 percent more for multi-family housing and 20 percent for single-family homes, Knezovich said.

But as more and more architects and builders are trained in passive house construction, these cost differences are expected to decline. The same is said of building materials required for passive house. Some passive house specialists estimate these buildings can be built at the same cost as conventional construction, especially when building low-income housing.

The selling point for passive house is the extremely low energy costs, which is why it is gaining momentum in the affordable housing market, Knezovich said.

“Every dollar saved has a really high value,” he said.

This long-term savings in utility costs is another reason PFHA is interested in passive house, Salwocki said. The projects awarded tax credits this year won’t be inhabited for at least two years. But once families start living in these homes, PFHA is planning to compare utility data from passive house projects with utility data from other energy-saving and conventional projects.

“The real benefit of this won’t be known for a few years,” he said.

As this utility data is gathered and reported from passive houses throughout the country, passive house will make sense to a lot of people, regardless of their opinions on climate change, Torres Moskovitz added.

“No matter if you’re liberal or conservative, paying less for your utility bills appeals to you,” she said. “Passive house makes sense because it performs better, is more comfortable and saves you money in the long term.”

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