Passive House – All About the Insides

passive-house
Gita Subramony for Zondits, October 7, 2015. Image credit: Curbed.com

Zondits recently attended an event on Passive House gut renovations hosted by the Building Energy Exchange. The presenters from Baxt Ingui architects showed a few case studies of recently renovated brownstones in Manhattan and Brooklyn landmark districts that incorporated Passive House standards in their process. The presentation showed that renovating old buildings to be supremely energy efficient is not only possible, but it can also provide lasting comfort for the occupants. These efforts can even dovetail with historic preservation goals related to building aesthetics.

Passive House describes a standard of construction that reduces energy consumption in a building to ultra-low levels. The standard can be applied to many building types, including residential and commercial buildings. Often, buildings that use these rigorous standards are net-zero ready. Passive House certification applies to new construction, whereas the program for retrofits is called EnerPHit. This certification can be especially useful for densely developed areas that feature old buildings, even those in historic districts. The EnerPHit standards help to improve building performance while preserving the architectural character of certain neighborhoods.

It’s not easy to identify a Passive House by its exterior. Curbed.com has put together a map of known Passive House residential buildings in New York City, and one look at the list shows a great variety of façade types and architectural styles. They look just like regular buildings; the difference is on the inside. One of the most important features of a Passive House building is creating an envelope with continuous insulation. Moisture barriers and tight construction allow the building to use less energy for heating and cooling purposes. Other common features include minimizing thermal bridges, high R-values for insulation, triple-glazed high-performance windows, and mechanical ventilation with an energy recovery ventilator.

It’s clear why would someone seek the Passive House standard. On top of a significant drop in energy use compared to baseline (up to 90% in some cases), there are added benefits such as noise reduction, increasing comfortable and usable space, and prevention of insect and vermin infestations. The methods used to make a Passive House building involve early planning and successful coordination between the design and construction teams. In addition, it relies heavily on quality construction methods. Some builders choose not to seek certification based on project costs or timelines, but they often incorporate some of the design and construction practices to achieve a low-impact and high-comfort space.

Passive House represents an area for growth as low-impact buildings become more desirable in the real estate industry. The presenters anticipate an immediate increase in this type of construction practice. However, it’s clear that the costs might present challenges (the case studies presented at this particular event were all high-end luxury developments). The real challenge will be implementing Passive House design and construction practices for market-rate and affordable housing.