Adopting European Passivhaus in the United States

While projects investigating Passivhaus, such as FXFOWLE’s study that uses a mixed-use high-rise pursuing LEED Silver as the base case, are making inroads, domestically, a number of factors are making the process somewhat challenging.

For starters, Piselli observes that European customs seem to accept spending money on the design and construction of high-quality buildings, whereas in the United States, there is a predisposition to cut costs at the expense of quality.

Furthermore, there are more aggressive political mandates and legislation governing energy-use reduction, in addition to the fact that northern and central Europe experience more temperate climates.

On the contrary, the United States has nine different climate zones, electrical plug loads are higher, and Americans prefer more artificial lighting, according to Nettleton.

“Culturally, people in Europe are more willing to accept a greater bandwidth of temperature swings,” Judah adds. In fact, “in Austria, some of the hospitals don’t even have air-conditioning.”

Another difference is that United States building owners, designers, and contractors aren’t used to the rigorous demands of the European Passivhaus system. “A degree of precision is demanded, which the United States building industry is not accustomed to accommodating,” Lamar explains. “However, it is clear than many teams are meeting this challenge and delivering excellent certified projects.”

That said, Europe also benefits from 20 years of experience designing and constructing Passivhaus buildings, whereas the knowledge base here in the United States is relatively small.

Yet another issue is the fact that the Passivhaus Institute bases its testing protocols on European standards. Here, the focus is making accurate predictions of the component’s performance in the context of its installation into a typical Passivhaus building so that the certification modeling results are accurate for use in PHPP building energy modeling, explains Snyder.

Some testing protocols in North America are focused on providing end users a single performance value for comparisons across product lines under a single set of test conditions that are not necessarily reflective of conditions in high-performance building envelopes like Passivhaus, Snyder says. Consequently, these test results cannot be used for accurate calculations of building components in Passivhaus buildings.

On the contrary, the PHPP software requires third-party test performance values for both the glazing units and frame components to accurately model the energy performance of windows of any size. However, in order to gather this information, manufacturers must be willing to undergo this testing, which is ultimately justified by a market for certified products.

“Unfortunately, the Passivhaus market has a harder time growing without the availability of precise performance values and certified products so it is a chicken-and-egg problem,” laments Snyder.

The metric versus imperial difference is a further complication when it comes to applying European Passivhaus standards to the United States.

“We are continuously needing to prod manufacturers for data that is in the European format,” Moelis says. “It’s encouraging that over the past few years, we’ve seen companies become more fluid, but it is difficult, for sure, as Americans are resistant to adopt European nomenclature.”

“Conversion is particularly burdensome during the submittal/shop drawing phase and leads to considerable challenges due to tight time constraints,” she adds.

Fortunately, PHPP software is available in both metric and inch-pound versions, helping alleviate the difficulty of converting units of measure.

Comparing Passivhaus to Other Rating Systems

While building teams have a number of sustainable building certifications to target when designing their latest high-performance facilities, Passivhaus is uniquely poised to deliver the very best in energy efficiency.

“The other systems cast a wider net and focus on a wider variety of environmental issues,” Nettleton says. “Each standard has its value, but there is really no comparison with these other systems when it comes to energy savings.”

“Passivhaus’ focus on energy efficiency, as opposed to a more holistic standard that tries to take everything on, means you get a superior building shell that is ‘future proofed’ for decades to come,” Hammer adds. “The efficiency performance is not watered down as it can be with other standards. It also facilitates actual deliver of energy performance much more effectively as verified by measured data.”

While some criticize Passivhaus as not fully focusing on operating energy and failing to set standards for other sustainability goals, Snyder points out that meeting the Passivhaus standard actually requires designers to address what she describes as other categories of green building goals.

“For instance, it isn’t possible to conserve enough energy to meet the Passivhaus standard if the designs doesn’t also practice extreme water conservation,” she explains. “And in an ultra airtight building like a Passivhaus, the impetus for eliminating VOC-emitting building materials becomes greater than ever, and the required ventilation mitigates remaining indoor pollutants.”

Furthermore, a Passivhaus envelope is foundational to achieving standards such as the Living Building Challenge and net-zero energy.

That said, LEED is practically considered standard practice, particularly in New York City, and some building owners would like to differentiate themselves. Highly proven in Europe, Judah anticipates that Passivhaus might be the next big thing here in the United States.

Bringing up another point, Nettleton notes that unlike some other rating systems, Passivhaus is not prescriptive and doesn’t dictate how to achieve the rating but only that the design hits the metrics. “This fact allows for creativity on the part of each team,” she says.

Handler agrees, explaining Passivhaus as a full-building design approach that gives the architect and engineer the freedom to meet certification requirements in a creative, independent manner.

“Passivhaus also allows the additional money spent to go into the quality of the building rather than third-party verification,” Nettleton adds.