The U.S. Coast Guard (USCG) housing in Honolulu, Hawaii, is located at the Kia'i Kai Hale Housing Area. The USCG converted 278 units in the complex from electric water heaters to solar water-heating systems with assistance from the Federal Energy Management Program (FEMP) and rebates from the local power providers.
The solar water-heating systems are active (pumped) open-loop systems with timers to control demand and tempering valves to allow higher storage temperatures without the risk of scalding. Solar water-heating systems are considered cost effective for the Honolulu area because Hawaii's relatively high energy costs and the consistent solar source. The USCG has also retrofitted its other housing units in Hawaii.
Initial investment: $4,000 per system (minus an $800 HECO rebate)
Payback period: 7.2 years
Cost savings: $446/year
Energy savings: 4,801 kWh/year