Passivhaus Windows, Made in the U.S.A.

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Two small California companies nab the first domestic window certifications from Germany’s Passive House Institute.

By Paula Melton

CaliPassiv Thermal Modeling


The PHI certificate for the CaliPassiv window includes these models along with U-values of individual components and installed U-values based on what type of assembly is used.

Renderings: Wooden Window

Casagrande Woodworks and Wooden Window, two small California manufacturers, have become the first U.S. companies to certify windows through the Passive House Institute (PHI), based in Germany.

Casagrande will reportedly begin production of its PHI-certified Synergist model, a wood casement window, this summer. The Synergist window is certified with a whole-window U-value of 0.139 (R-value of 7.2).

Wooden Window expects its CaliPassiv line (which currently includes one fixed and one operable wooden window, both with aluminum cladding) to start rolling off assembly lines in the next few months. Both models boast a whole-window U-value of 0.137 (an R-value of 7.3).

Any product that contributes to the stringent overall energy requirements of the Passive House building standard can be used in a Passive House project—in theory. However, the Passive House Planning Package (PHPP) modeling software used to assess whole-building energy performance requires certain data not usually measured or reported by U.S. window makers, who typically use the National Fenestration Rating Council (NFRC) system. Most North American project teams have imported European windows for Passive House buildings.

Two U.S. window manufacturers—first Alpen and then Marvin—have achieved certification for some window models under the separate Passive House Institute U.S. (PHIUS) program, which rates windows by climate zone. PHI severed ties with PHIUS in August 2011. The two window certifications are not the same, but both Passive House programs base their certifications on modeling only; NFRC’s program requires physical testing as well.

For more information, download the press release from the Passive House Institute.

Comments (1)

1 PASSIVE HOUSE NORTH 2013 posted by Andre Harrmann on 09/16/2013 at 11:54 am

Casagrande and Wooden Window are going to present their windows at the Passive House conference in Vancouver: The Canadian Passive House Institute (CanPHI) will host the first North American Passive House conference dedicated to cost-effective strategies for reducing building energy in cool climates. PASSIVE HOUSE NORTH 2013: Affordable energy efficiency for a changing climate will convene Sept. 27 and 28 at the Westin Bayshore in Vancouver, B.C.

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July 28, 2013