In a statement released on May 23, the Harvard Center for Green Buildings and Cities (CGBC) announced its plans to retrofit its headquarters, a pre-1940s stick-built house in Cambridge, Mass. into an ultra-efficient, energy-positive building. Called HouseZero, the project will serve as an example of how to apply energy-saving construction principles to existing homes and buildings.
The CGBC says, “Rather than approaching the house as a ‘sealed box,’ the building envelope and materials of HouseZero are designed to interact with the seasons and the exterior environment in a more natural way.”
When complete, HouseZero will have no HVAC system, relying regularly on added thermal mass and radiant surfaces, and a geothermal heat pump for extreme conditions. Heating and cooling will be adjusted using a solar-powered vent and an automated system, which monitors temperature, humidity and air quality, and opens windows to create natural cross ventilation.
Whenever possible, HouseZero will rely 100 percent on natural light, utilizing a design that maximizes the amount of daylight let inside. Rooftop solar panels will also be carefully placed to maximize the direct and indirect sunlight they collect to produce the small amount of energy needed.
Additionally, the building should produce no carbon emissions, including from the embodied energy in its materials and all of the components of the building will be outfitted with sensors to collect data for use in research and development of energy-efficient technologies.
Energy-efficient practices, like those at HouseZero, are becoming common in new buildings, especially as cities adopt them as requirements instead of as ideals as the Fremont City Council did on May 2, voting to require new housing developments to install solar panels and wiring for electric vehicle stations.
Although positive, a focus on new construction fails to address the energy consumption and pollution created by buildings already standing. According to the International Energy Agency, buildings account for 41 percent of the energy used in the U.S., and housing accounts for nearly a quarter of those buildings.
"Before now, this level of efficiency could only be achieved in new construction," said Ali Malkawi, professor of architectural technology at the Harvard Graduate School of Design, founding director of the CGBC and the creator of the HouseZero project. “We want to demonstrate what's possible, show how this can be replicated almost anywhere, and solve one of the world's biggest energy problems—inefficient existing buildings."
Although the headquarters will house offices for researchers, the CGBC says they view HouseZero “through the lens of the home renovation market,” hoping to demonstrate how homeowners can pair better design and technology to improve their energy and carbon use, which should save them heating, cooling and powering costs in the process.
All this, the CGBC says, can be achieved without costly or wasteful teardowns using technology already on the market and available for homeowners to purchase.
Construction on HouseZero will take between seven and nine months.