Performance - A Case Study

David Shepler, the first resident of Green Acres, tracks the daily performance of his home. He moved in on 27 Mar 2009, and below you can see his energy performance and comments. The Greenhill Contracting website has asked David to update his performance regularly for the interest of all those curious about the performance of our homes and zero energy concepts more broadly.

Characteristics of David's home (featured in photos to the left):
- Size: ~3,000 Square Feet
- Energy Production: 10 kW Photovoltaic System
- Other Energy Features: Geothermal HVAC (Ground Source Heat Pump), Insulated Concrete Form (ICF) construction, high-performance windows, and heat-recovery ventilation.

Performance since 23 Apr 09 (when the automated monitoring system, provided by Locus Energy, was activated):

Comments from David:

- The dark red line references the Net Consumption axis on the right. This shows that the house continued to produce electricity faster than it could consume it until 11 Oct 09, when consumption through the winter months has turned the line around. The house built up an electricity "reserve" of 3,695.88 kWh. Through the end of December, the house has given back almost 1,000 kWh because of some persistent snow cover on the panels and cold temperatures. January and February 2010 should continue to show net positive consumption before beginning to taper off in March.

- I also saw the effect through Oct and Nov of leaving a tree at the southeast corner of the house, which brought significant shading in the morning hours. I decided on 12 Feb 2010 to take the tree down, and I've already noticed an increase of a few kWh daily.