The Public Utilities Commission has halted a plan by Hawaiian Electric Co. to help its customers finance solar water heaters, saying the utility’s program did not appear to be cost effective and preempted a broader “on-bill financing” study being conducted by the PUC.

HECO on Jan. 3 unveiled its “Simply Solar” program in which the it proposed to pay the upfront cost of solar water heating systems and have customers pay back the utility in monthly installments on their electric bill. HECO said it had hoped to launch the program, aimed at renters and lower income residents, within 60 days.

The PUC said while it was “suspending” the $55 million Simply Solar program it would consider allowing HECO to continue it as a “potential interim option” while regulators study the feasibility of creating an on-bill financing system designed to help utility customers to pay for a wider array of energy-saving devices and appliances.