In this work, a hot water tank was developed to improve the performance of energy-saving and heat storage based on the source-sink matching principle. Through the source-sink device, the excess heat at the upper boundary of the tank could be absorbed by a heat collecting chamber and transmitted through the heat pipes to the bottom heating plate for reuse. The reasonable distribution of heat was realized while the heat insulation was improved. A comparison experiment regarding the charging and discharging processes between the improved and conventional hot water tank was tested to verify the performance enhancement. The results showed that the total exergy efficiency of the improved hot water system was increased by 7.6%, and the exergy efficiency of the water tank was 25% higher than that of a conventional tank. The heat loss of the upper layer of the tank was reduced by 55%, which indicated the improved water tank had a noticeable energy-saving effect. In addition, the total amount of available hot water in the improved tank was twice that of the conventional tank under the same operating condition. The improved hot water tank was more aligned with the users' demand for hot water.