Innovation

High energy performance with low tech residential design

Resembling a traditional Hudson Valley barn, New York's first certified Passive House was designed by architect Dennis Wedlick with support from the New York State Energy Research and Development Authority.

Written by Sun Kim, Contributor Oct. 20, 2011 at 11:23 p.m. PT

The Hudson Passive Project is the first certified Passive House in New York state and among the most energy efficient homes in the world. The house is a prototype energy conservation project built as part of the state's High Performance Energy Challenge, a program to increase knowledge and experience in building cost-effective, energy efficient residential projects. Designed by architect Dennis Wedlick, the house will achieve near zero energy consumption.

Based on the rigorous standards for energy efficiency established by the German Passivhaus Institut, the three bedroom house uses 10 percent of the energy of a standard US house. Without geothermal, wind, or solar panel systems, buildings meeting Passivhaus (in the US, Passive House) standards must be super insulated and primarily heated by the sun and the people occupying the building. In the Hudson Passive Project, the simple elements of a large south facing glass wall and a concrete floor that acts as a large thermal mass provide most of the house's heating and cooling.

Where LEED is a point based certification system, the Passive House standard has only three criteria and all three are energy based. The three criteria are:
1. an annual heating/cooling demand of not more than 15 kilowatt-hours per square meter (4,733 BTU per square foot),
2. an annual cap on total use of primary energy (heating, cooling, water heating, electricity, etc.) of no more than 120 kilowatt-hours per square meter (409,456 BTU per square foot), and
3. a limited air infiltration of no more than 0.6 times the house volume per hour at 50 Pascals (tested by a blower door)

The Passive House certification process involves verification of the three requirements through a proprietary software which analyzes projected energy use throughout the design. By inputting design modifications, designers and building owners can see where there is room for play and improvement such as the size of windows and thickness of walls.

Wedlick tackled the air infiltration limit, usually the biggest challenge for designers and builders, by using an alternate method of frame construction. Since standard stud construction results in lots of joints that require applied seals, Wedlick opted to wrap the walls and roof with structural insulated panels (SIPs). The SIPs form a uniform, tight, and highly insulated layer outside of the structure.

The design of the home reflects the historical structures of its Hudson Valley region. Instead of a rigid modern box, the house resembles an old stone barn. It was even constructed as such, with an old fashioned raising of its bow-arch beam frames.

Wedlick states that ”During the design process, we kept coming back to the core concept: It’s not the technology, it’s the architecture. We want to empower industry practitioners and homeowners with the understanding that better-built, better-designed homes can be a powerful and relatively simple way to conserve our nation’s resources.”

Almost prescribed by the Passive House standards, the house's southern glass face allows views of the outside as well as the calm interior. The Hudson Passive Project is a cozy reminder that with good planning and good intentions, modern energy efficient design does not have to be complicated or stark.