The pipes used to circulate water in a solar collector usually has 'parallel' configuration. The water would absorb more solar energy if it flows slower in the pipes. It could be accomplished by using 'serpentine' configuration. A research on a 'parallel' collector and a 'serpentine' collector was carried on the same time, which were 7 days for one cover glass and the next 7 days for two cover glasses. From the research, it is found that if the water stored in a reservoir tank is to be used in the evening, 'parallel' configuration is more suitable than 'serpentine' configuration.