General Energy Use, Strategies and Systems

Energy Use:

The shell and energy efficient features of this home are highly repeatable. The cost to get to zero energy has been brought down to $3 per square foot over a stretch code home with a leased PV system. At these prices, the zero energy homes can spread fast throughout Massachusetts and other states with Solar Renewable Energy Credits. It is Transformations goal to help speed this process. The typical home saves about 60% of its energy in the shell, appliances, lighting, hot water, etc. The other 40% or more is made up though the PV.

Energy Strategies:

The Groton features a 7.14 kW PV system that is integrated into the surface plane of the roof for a pleasing aesthetic. We attained the look of BIPV without the cost! The roof under the PV system was recessed 8” inches to accomplish this. Black framed mono-crystalline panels further this curb appeal.

Zero Net Energy Definition Used Source Energy Use

Monthly Energy Data and Utilities

Energy Data Type:
Electric Utility:
Unitil Gas and Electric
Gas Utility:
Unitil Gas and Electric
Datasets and utility bills:
Datasets and utility bills sources and reliability:

source of the data is utility metering. Net electricity consumed including the gas w/conversion is -1574 kWh

Renewables and Energy Balance

Renewable Energy Sources:
Renewable energy is generated within the building footprint (e.g. solar PV on the roof)
Renewable Energy System Description & Details
Utility only provides net usage. See utility bills for supporting data. (42) Suntech 170 watt mono-crystalline panels in black frames; (1) Solectria PVI 3000 inverter and (1) Solectria PVI 4000 inverter Peak power rating is 7.14 kW Projected annual production is ~8,000 kilowatts per year.
Annual Renewable Energy Generated Data Type Measured
Renewable Energy System Type(s) Source of Annual Production Data
Photovoltaics metered by utility

Annual Energy Import/Export

Net electricity usage (purchased electricity) -2,510 kWh/year
Natural gas amount (purchased energy) 936 kWh/year