General Energy Use, Strategies and Systems

Energy Use:

The Mini Split Heat Pump is set up with the interior unit 18" up off the floor to enhance its heating performance. Heated air is blown out across the floor. This puts the wormed air where the occupants are and it stirs up all the cool air sitting on the floor. The outside unit is set up in the south wall of the porch such that its intake air is pulled out of the porch prewarmed much of the time and never loaded with snow.

Energy Strategies:

First all electrical devices and appliances were selected for minimum electrical use. The PV array was sized to more than meet the electricity use on a yearly basis.

Zero Net Energy Definition Used Site Energy Use

Monthly Energy Data and Utilities

Energy Data Type:
Electric Utility:
Central Maine Power
Other purchased Fuels:

We use about 10 gallons of propane each year to power the gas stove.

Datasets and utility bills sources and reliability:

Data is from reliable utility bills.

Renewable Energy System Description & Details
6 kW PV, 24 MAGE 250 watt powertec plus modules in three paralleled series strings. Inverter is a Solectria PVI 6500 unit located in the crawl space. Modules are mounted on the seams of the metal roof with S-5 PV clips.
Annual Renewable Energy Generated Data Type
Power Rating Renewable Energy System Type(s) Source of Annual Production Data
6,000Watts Photovoltaics Actual metered array output

Storage and Installed Capacity

The hot water tank is on a timer such that it only comes on during daylight hours when the PV array is supplying electricity. All windows are high efficiency but still have quilts that raise R values, reduce infiltration and increase surface temperatures.

Energy systems description:

Thermal Energy is stored in the hot water tank and in the mass of the house.

Energy Storage Capacity

Annual Energy Import/Export

Electricity amount (imported from grid) 1,738 kWh/year
Net electricity usage (purchased electricity) 1,738 kWh/year
Electricity amount (credited or exported to grid) 9,192 kWh/year
Natural gas amount (purchased energy) 269 kWh/year