My energy provider (BGE) used to offer a program where you could get a rebate in exchange for letting them control your hot water heater and/or thermostat. The

My energy provider (BGE) used to offer a program where you could get a rebate in exchange for letting them control your hot water heater and/or thermostat. The HVAC portion is still running, but only for people who signed up prior to 2020. The water heater program has been completely stopped since 2021. The good thing with both approaches is you don't need the appliance built to support it. For HVAC, the control system is in the thermostat, which is cheap and has a standard interface. For waterheaters, you can just stick a relay in sequence with the heater.