Connected (smart) water heater
A connected water heater has Wi-Fi and app control: scheduling, vacation mode, leak alerts, and — the financial hook — eligibility for utility demand-response programs that pay you for letting the utility shift heating to off-peak hours.
Because a tank stores hot water, shifting when it heats costs almost nothing in comfort — which makes water heaters the ideal demand-response appliance. Many utilities pay enrollment or annual credits for certified connected units.
The certification record lists connected capability as a yes/no field; some models need an add-on module, so check what is in the box.