A solar hot water system supplements a conventional heating system but does not replace it. Solar water heaters reduce the cost of running conventional commercial and industrial boilers by preheating the water that enters these systems. The boilers take care of heating needs at night and on cloudy days.

Solar hot water systems may cost more initially than conventional fossil-fuel systems but, over time, they can save businesses a substantial amount of money and reduce GHG emissions. At current energy prices, these systems may pay for themselves in 5 to 10 years, depending on the application. Of course, if the price of conventional fuel rises, payback time will be reduced. A solar hot water system reduces the amount of fuel used for heating, thereby saving money and conserving natural resources for the community at large.