Building at a Glance – Roxbury E+ Townhomes

Sam Oberter Photography
 

Building at a Glance
Name Roxbury E+ Townhomes
Location Boston
Owner Private
Principal Use 4 townhomes
Occupants 13
Expected (Design) Occupancy 16 (4 per home)
    Percent Occupied 81%
Gross Square Footage 7,883
    Conditioned Space 7,883
Distinctions/Awards AIA COTE Top 10, 2015; LEED for Homes Platinum, 2014
Total Cost $1.5 million
    Cost per Square Foot $194.72
Substantial Completion/Occupancy 2013

Energy at a Glance
Annual Energy Use Intensity (EUI) (Site) 15.18 kBtu/ft²
    Electricity  (Grid Purchase) 15.18 kBtu/ft²
Annual On-Site Renewable Energy Exported 17.02 kBtu/ft²
Annual Net Energy Use Intensity –1.84 kBtu/ft²
Annual Source (Primary) Energy –5.79 kBtu/ft²
Annual Energy Cost Index (ECI)* $0.47/ft²
Savings vs. International Energy Conservation Code-2009 Design Building 59%
Carbon Footprint 11.6 lb CO₂e/ft²•yr
Percentage of Power Represented by Renewable Energy Certificates** 100%
    Number of Years Contracted to Purchase RECs 10
Heating Degree Days (Base 65˚F) 5,651
Cooling Degree Days (Base 65˚F) 921
Annual Hours Occupied 8,760

*Energy cost index reflects cost of electricity used from grid. However, each of the four homeowners was able to generate enough electricity through renewables within the first year of operation to "bank" credit with the utility company, resulting in no electric bills.

**The homeowners receive solar renewable energy certificates (SREC) based on the size of the photovoltaic system. Each owner receives approximately 10 certificates per year, which they may sell in the SREC market. As the homes ultimately produce more than they consume, we concluded that 100% of power used is represented by SRECs. However, users buy electricity from the grid and then sell back generated electricity to the utility.

Check out the full case study here.