The invention discloses a phase-change heat-
storage energy-saving electric 
water heater and belongs to the technical field of household appliances. The 
water heater comprises a shell, an insulating layer, an inner tank, a 
magnesium rod, a 
sewage draining exit, a hot water outlet, a cold water inlet, a leakage protection switch, a temperature controller and an 
electric heating pipe, wherein the insulating layer between the shell and the inner tank is a composite insulating layer which consists of a 
polyurethane foam heat-preservation layer and a phase-change heat storage layer; the energy saving of a 
water storage electric 
water heater is realized by the double insulation of heat storage and heat insulation; the 
polyurethane foam heat-preservation layer is positioned between the shell and the phase-change heat storage layer which is tightly attached to the outer side of the inner tank; the composite insulating layer is 25 to 45mm thick; and the thickness ratio of the phase-change heat storage layer to the 
polyurethane foam heat-preservation layer is 0.4 to 0.8. The electric water heater has the advantages of capability of improving the energy saving level in a 
water storage and heat preservation process and reducing 
power consumption, 
high heat utilization ratio, safety and low cost, and is 
environmentally friendly and convenient for operation.