This paper presents the evaluation results of conventional solar water heater (SWH) systems and solar
assisted heat pump (SAHP) systems for hot water production in Hong Kong. An economic comparison
and global warming impact analysis are conducted among the two kinds of solar thermal systems and
traditional water heating systems (i.e. electric water heaters and towngas water heaters). The economic
comparison results show that solar thermal systems have greater economic benefits than traditional
water heating systems.