The State of Hawaii has a law that mandates the use of solar water heating for new construction. There are alternatives such as on demand gas heaters, electric heaters powered by solar panels and inverters, and heat pumps.
Solar capacity is limited by trees, clouds, darkness, and angle to the sun. They make up for these inefficiencies by requiring a large storage tank that has an electric backup element.
If the cost of a solar water heater is adjusted by tax credits from the federal and state governments (and in some cases the local electric company) the systems can easily pay for themselves in savings from the electric bill in a couple of years, and will keep on heating your water for its lifetime with very little further maintenance cost. Almost Free !
Gas heaters have an initial cost determined by the size and sophistication of the system, and will always require the purchase of propane.
The amount of energy needed to heat water electrically with solar panels would require a lot more panel array than could be done with direct solar heating.
Heat pumps are a good solution for heating electrically because they are more efficient than direct element heaters.
and we invite you to come down and see us or give us a call.