Hawaiian Electric's $2.5 million payment backlog to contractors in its solar water heater program detracts from its success.

The program helps Hawai'i homeowners and businesses escape from nation-leading electricity rates in the state while cutting down on the amount of imported foreign petroleum used in the generation of electricity here.

HECO said more than 50,000 systems have been installed during the 13-year program and that statewide, more than 80,000 solar water heaters have been installed. It's estimated the solar water heating program has reduced annual demand for electricity by 111.3 million kilowatt hours annually, or about the estimated annual usage of 14,000 households.

For homeowners, the economics of the program are compelling when combined with 30 percent federal and 35 percent state tax credits that are available.

HECO estimated the net cost to homeowners in 2007 for an average system was $1,487 once the $1,000 rebate and tax credits were subtracted from the total cost of $5,250.

For a four-person household where water heating costs run $50 a month, the system would pay for itself in less than three years.