The retrofitting of existing buildings is a central component of the climate action plans of virtually every city in North America.  Many of today’s buildings were constructed in an era of inexpensive fossil fuels, the impacts of which were largely unknown.  The opportunities to lower emissions by improving energy efficiency in buildings is significant and most of the simplest available measures are well understood and are regularly implemented in buildings of various types.  However, while many buildings perform efficiency upgrades to individual systems, there are limited examples of occupied buildings that perform the type of integrated retrofits that are likely needed for most cities to meet their climate action goals.  Upgrading existing buildings will require significant resources and in addition to raw efficiency must also deliver a high quality environment, be primed for a future powered by renewable energy, and provide resiliency in the face of future climate fluctuations and crises.

For this study we have selected an existing building in New York City, one typical for a large segment of the city, and analyzed what measures would be necessary to deliver the most comfortable building for the occupants while using the least amount of energy.  To analyze how to reach this dual goal of human comfort and energy efficiency we have utilized the Passive House standard for existing building retrofits: EnerPHit.

The analysis described throughout this report was performed jointly by Steven Winter Associates in New York, New York and the Passive House Institute (PHI) in Darmstadt, Germany.  PHI are the original developers of the Passive House standard, which they continue to refine, and among many other activities administer the international network of accredited Passive House certifiers.  The emphasis in the study is on selecting the required energy conservation measures, and how these might be phased in over time while the building is occupied.  More briefly, we will also describe code and regulatory barriers to pursuing this deep retrofit, the most important technical and market challenges, and how capital planning for such measures might be organized.  The goal of this work is providing a high level guidance document that will allow similar such buildings  to envision a phased deep retrofit of their own building in the absence of relevant examples.


Report: Publication anticipated Spring 2018


  • Deep Retrofits
  • Retrofit
  • Passive House / High Performance
  • Passive House

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