Chris Van Arsdale shares pictures and information from this solar installation on a townhouse in Washington D.C. This house produces electricity and hot water using solar panels. These two products are a result of photovoltaic solar panels and solar thermal panels. This presentation was given December 4, 2009 at the Solar Energy Focus Conference: Fall 2009 hosted by the Maryland, DC, Virginia Solar Energy Industries Association (MDV-SEIA) in Gaithersburg, MD. To learn more please visit: www.mdvseia.camp7.org

1. 19th Street, NW DC

2. System Description:
• 2.9 kw pv system
• Gridpoint inverter/battery backup/ dashboard
• 9 4’x10’ Helodyne thermal panels (DHW and radiant floor heating)
• 6 80gal. water storage tanks

3. Energy Efficiency

4. Installation Issues

5. PV
Total renewable produced (2yrs) 10,298 kwh
Total Grid Purchased (2yrs) 20,538 kwh
Energy production value $617/yr (avg)
Total system cost (incl. frame)
(after $15k DC grant) $19,000
Average annual ROI
(without RECs) 3.2%

6. Solar Thermal
• System cost (incl. frame) $28,000
• Avg. Annual Savings (heat) $928
• Avg. Annual Savings (dhw) $200
• Avg. Annual ROI 4%

7. Lessons
• ROI without subsidy not great
• Solar thermal for heating = maintenance
hassle
• Thermal system returns less than
expected
• Better option: Thermal for DHW/ More
PV/ Ground-source heat pump HVAC