HouseZero® (HZ), which serves as the headquarters for the Harvard Center for Green Buildings and Cities (CGBC), also functions as a living laboratory. HouseZero is continuously collecting data to inform necessary improvements, to enhance our understanding of building performance, and to conduct experimentation. This page provides real-time energy, indoor temperature, and carbon-performance data for HouseZero. Microclimatic data of temperature, solar radiation, wind speed, and wind direction are also provided. This information is provided as part of the CGBC educational mission: to promote heightened understanding of building performance through data and building science.
Every building is subject to varying weather conditions that influence its performance. Microclimatic conditions of temperature, solar radiation (total horizontal radiation W/m2), wind speed, and wind direction from the onsite HZ weather station are displayed. These two weather data points are presented in three formats: Instantaneous, Weekly, and Monthly. Each format corresponds to the energy data displayed.
The energy data shows building energy use, photovoltaic (PV) production, and the net value (PV production – Energy Use). A positive net value indicates more energy being produced than used during the period. These three key data points are displayed in four figures:
Interior building temperature is also displayed in hourly-average format (hourly indoor average temperature), showing the last 24 hours and updated hourly. In addition, it is displayed in daily average format (daily indoor average temperature), updated daily and showing the last 30 days.
Detailed information regarding HZ data can be found in the peer-reviewed papers:
"Comprehensive Assessment of Operational Performance of Coupled Natural Ventilation and Thermally Active Building Systems via an Extensive Sensor Network”
and
“Data-Informed Building Energy Management (DiBEM) towards Ultra-Low Energy Buildings: The Case of HouseZero.”
View summaries of the first and second-year data.
HouseZero has relatively low embodied carbon for a building of its type. This was carefully planned given its constraints (operating as an office space and experimental laboratory) and aims to maintain the lowest possible operational energy. Detailed information regarding its embodied carbon is fully described in the peer-reviewed journal paper Zero-carbon balance: The case of HouseZero, which includes the full lifecycle assessment (LCA) data. This paper includes both HouseZero’s carbon balance over a 100-year estimated building life and the carbon balance for a 60-year estimated building life. The paper provides a transparent and complete LCA, including all systems and stages, to support external use of the Center’s data, to help inform future benchmarking models, and to derive methods for estimating complete LCA data based on a limited LCA study. Read a summary of the paper.
When temporal and physical system boundaries are aligned to current benchmarking studies, the normalized embodied CO2e emissions of HouseZero is 233 kg CO2e/ m2 (initial embodied CO2e in the product and construction phases without technical systems).
Adding the technical systems in HouseZero, the total initial embodied CO2e in the product and construction phase including all technical systems (as detailed in the paper) is 295 CO2e/m2.
For the 100-year estimated building life of HouseZero, the embodied carbon emissions per square meter of occupied space of HouseZero is 326 kg CO2e/m2. When calculated for 60 years, the total is 297 kg/Co2e/m2. These calculations include carbon emissions generated from the extraction, manufacturing, construction, and replacement of all elements considered to be within the building’s physical system boundary. It incorporates the building’s material systems (e.g., building assemblies including the foundation, structure, enclosure, and interior partitions and finishes) without technical systems.
When technical equipment not typically included in most similar studies (e.g., energy well, heat pump, photovoltaic panel and balance-of-system, and elevator) are added to the above, the embodied carbon emissions per square meter of occupied space of HouseZero is 488 kg CO2e/m2 when calculated for the 100-year estimated building life of HouseZero and 412 kg/Co2e/m2 when calculated for 60 years.
Four different grid emissions methodologies are analyzed to illustrate the calculation’s impact on HouseZero’s carbon balance estimates. The aim is to highlight the importance of additional research into real-time emissions estimation at the building level.
The graphs below show results from these analyses, including offset emissions for solar PV production, operational energy use, embodied carbon emissions, and resulting net carbon balance. They show the yearly data balance, based on 100 year LCA calculations. Positive net energy production results above equate to negative net carbon emissions (offset emissions) in the data below. Given the differences in methodologies and inputs, the magnitude of calculated emissions should not be compared between methods. Using existing standards, operational emissions are based on total load, without IT (e.g., data servers) and plug loads. We estimate embodied carbon emissions generated from the extraction, manufacturing, construction, and replacement of all elements considered to be within the building’s physical system boundary. These calculations include the building’s material systems (e.g., building assemblies including the foundation, structure, enclosure, and interior partitions and finishes) but exclude technical equipment that are not as typical in most studies.
Two time periods are depicted in the series of graphs below: left-panel graphs show the most recent year-to-date cumulative carbon, and right-panel graphs show the total cumulative carbon to date. Both year-to-date and cumulative estimates will be updated monthly.
Total carbon for current year to date
Total yearly accumulative carbon to date
Total carbon for current year to date
Total yearly accumulative carbon to date
Total carbon for current year to date
Total yearly accumulative carbon to date
Total carbon for current year to date
Total yearly accumulative carbon to date