Although the Dreese home's roof faces southwest rather than the more ideal due south, production from the PV and solar hot water panels has been as much or more than projected. There is absolutely no shading, which is probably more important than the exact orientation. Electric production is higher in the late afternoon when the load on the grid peaks. The ground-source heat pump is quieter than most refrigerators.

Read more about the Dreese residence in the August 2008 issue of The Solar Flare.

System Components

Additional Sustainable Features

Designer/Engineer/Installer

Innovative Power Systems and UMR Geothermal

Date of Installation Completion

Ground-Source Heat: December 2006

Solar Hot Water: October 2007

Solar Electric: January 2008

System Cost, Payback, and Financial Incentives Utilized

Ground-Source Heat: $18,600 minus $500 federal tax credit = $18,100 net cost

Solar Hot Water: $9,600 minus $2,000 federal tax credit = $7,600 net cost

Solar Electric: $40,000 minus $7,800 state rebate and $2,000 federal tax credit = $30,200 net cost

Anticipated Energy Delivery When Purchased

Solar Hot Water: Replaces about 130 therms/year of natural gas

Solar Electric: Produces about 4,800 kWh/year

Ground-Source Heat: 7–8 kWh of electric energy will replace 1 therm of natural gas

Actual Energy Delivered When Installed

All 3 systems are meeting expectations

Percentage of Total Energy Needs Delivered

Electricity: 50%

Natural Gas: 80%