It is recommended to properly insulate DHW storage tanks to limit heat losses. Insulating the hot water tank is an easy and inexpensive way to improve energy efficiency and save money. For an electric water heater, it also might be considered insulating underneath the tank as well.
Reduce standby heat losses by 25%–45%
Be sure that the water heater is not leaking. If the tank leaks, a new water heater is needed
Initial investment: pre-cut jackets or blankets available from around 20 €. Some utilities even install these at a low or no cost.