Harvard HouseZero: Net Energy Gain
Energy-Producing Property
Harvard HouseZero: Net Energy Gain
CGBC Headquarters: HouseZero
The Harvard Center for Green Buildings and Cities (CGBC) has retrofitted its headquarters, a pre-1940s building in Cambridge, MA, into a laboratory that will help us to understand buildings in new ways. A first-of-its kind test case, it also functions as a prototype for ultra-efficiency. Targeting the most rigorous efficiency standards ever achieved by a building retrofit, HouseZero has the following performance goals:
• Almost zero energy required for heating and cooling (No HVAC system)
• 100% natural ventilation
• 100% daylight autonomy (No daytime electric light)
• Zero carbon emissions, including embodied energy in materials
How can a building have no need for an HVAC system and electrical lighting during the day?
Harvard HouseZero addressed that question in several ways…
replaced the HVAC system using a different paradigm which relies on additions of thermal mass and radiant surfaces throughout the building.
geothermal (ground-source) heat pump was installed
solar vent is used to instigate buoyancy-driven natural ventilation.
natural cross ventilation is used to adjust heating and cooling needs throughout the house
materials will help to control fluctuations in humidity by naturally absorbing and releasing moisture in the air.
renovation improved the insulation level of the building envelope, combined with a high-level of air tightness whilst ensuring sound building physics.
source: Harvard HouseZero
Author’s note: a truly remarkable project for building science and energy production and usage calculation. Update: 2025 - data continues to be shared about the net energy gain for the property. Geothermal proves to be an important element in energy production and HVAC considerations. The future is geothermal. -Marky
