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Posted by sofia on Monday, August 16th AT 05:06:00 PM

Our last post explored the larger transformations of this building, including unit and layout conversions that gave our client an open duplex in addition to a rental flat. We’ll now take a look at how Passive House works in an historic building.


Passive House Principles

The core principles of the Passive House standard are rather simple: insulation, airtightness, prevention of thermal bridges and energy recovery ventilation.

Along with a thick and continuous thermal insulation layer to keep temperatures comfortable, airtightness prevents infiltration of outside air as well as the loss of conditioned air. The building envelope needs to pass progress and final blower door tests, which confirms the airtightness of the exterior walls.

During design, it is also critical to identify and remove any “thermal bridge” conditions, which are moments where building materials act as channels for transmitting outdoor cold (or heat) to the indoor spaces.

We look closely at all construction details, material specifications, and weather-proofing details, including everything from well insulated high-performance windows to the execution of corners, connections, and penetrations.

Finally, all the fresh air that is drawn into the building is filtered and passed through an energy recovery ventilation system that retains up to 90% of the heat (or cooling) that would normally be lost through exhaust. 

How does this work in an existing building, especially when it’s landmarked?


Previously We took a closer look into the architectural design and layout changes, ultimately converting the building from a three-family to two-family townhouse and bringing with it increased openness and light.

Up Next: We’re showing some insights into the demolition phase and structural work, a precursor to getting this building airtight and ready for Passive House standards.