Seeing Passivhaus in a Whole New Way
This thermal image really is worth a thousand words
Designers are accustomed to talking about high-performance houses in a language of abstractions: R-values, triple-pane windows, and blower-door testTest used to determine a home’s airtightness: a powerful fan is mounted in an exterior door opening and used to pressurize or depressurize the house. By measuring the force needed to maintain a certain pressure difference, a measure of the home’s airtightness can be determined. Operating the blower door also exaggerates air leakage and permits a weatherization contractor to find and seal those leakage areas. results. We sort of get it. But this thermal image makes the dramatic difference between a Passivhaus project and conventional construction really easy to understand.
The blue rectangle in the midst of all those oranges and reds is New York City's first certified Passivhaus project, a retrofit of a 1899 townhouse in the Park Slope area of Brooklyn. Blue is cold, meaning the exterior surfaces of the house aren't shedding energy. Around it are houses glowing with wasted energy.
The name of the project is Tighthouse. The team responsible for Tighthouse includes project manager Julia Torres Moskovitz, the principal of a firm called Fabrica 718, and a number of collaborators. You can read more about the project at Moskovitz's web site by clicking on the green tab under "Projects."
One of the key requirements for Passivhaus certification in new construction is a blower-door test result of 0.60 air changes per hour at 50 pascals (ach50). Retrofits need to meet a different standard (EnerPHit) with a slightly relaxed standard of 1.0 ach50. This project came in at 0.384, Moskovitz says.
Her book about Passivhaus construction, "The Greenest Home: Superinsulated and Passive House Designs," will be published by the Princeton Architectural Press on June 4.
- Sam McAfee/SGBuild
May 8, 2013 5:05 PM ET
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