Best way to control 240V water heater?

[rhino]

What would be the best way to control a 40 gal. 240V 4000W electric water heater? I'd like ability to configure it not to run at night and possibly not run if not generating enough power for the day. Was possibly thinking of some Shelly relay that can trigger a 2 pole relay but not sure if that is best option or what relay to get.

Was also still thinking about converting it to 120V which would simplify things since a Shelly relay could control it directly but worried about time the tank would take to recover.

 

[Cuemaker]

I use this,

https://www.amazon.com/DEWENWILS-Mechanical-Outdoor-120-277-Programmable/dp/B09TSWQLW5/ref=sr_1_3?crid=Z7T4X7LWCZ58&keywords=dewenwils+timer+hot+water&qid=1703040123&sprefix=dewenwils+timer+hot+wate%2Caps%2C527&sr=8-3

 

[WindWizard]

A Solid-State Relay will work. Make sure that you use a good heat sink with it. You can decide what voltage you would like to control it. I am using one to control a pool pump. When the pipes heat up then it turns on the pump to run water through the pipes. This heats up the water in the pool.

 

[SupraSPL]

I wired mine for 120V and use a wyze wifi plug to turn on and off. free app and has a timer and schedule.