I’m looking for the best way to control the flow of electricity for a second/weekend house.
Most importantly I would like to be able to control the Hot Water Heater. Other things would be nice, and those capabilities exist but I just haven’t seem to be able to find a good way to control the hot water.
What about a smart circuit breaker? Does anyone have experience with these?
Any feedback, opinions, or experiences would be greatly appreciated.
I don’t know of any smart circuitbreakers, and I doubt if they would be to code. But I think most people would just use an in-line relay for something like that. You do have to match the specs on the line where you’re installing it and of course on the device at the end.
What’s the brand and model of the water heater?
BTW, here is a similar project except that the home already had a dumb timer cut into the circuit for the hot water heater. You’d be taking essentially the same approach, except one step earlier in the process as that one already had a switch on the line.
Agree with JD:
You need to get the specs of your hot water heater. Then a 240v relay like this one may possibly work;
https://byjasco.com/products/ge-z-wave-plus-direct-wire-indooroutdoor-smart-switch-40a
It’s the same device that many on this community are using to automate their pool pump. You can search for that to see many similar threads. Same solution for a different appliance.
Thanks everyone, I didn’t even think of using a switch, I’m kind of new to this so overlook my ignorance.
Luckily I can spec the hot water heater to fit the switch, I’m getting a new one.
Again I appreciate the responses.
If you’re getting a brand new hot water heater, then you have more options, as there are some smart models that will work with IFTTT, so you can get smartthings integration that way. Then you have a lot more choices than just on and off. But as you might guess, they also cost more. So it depends on what you want to accomplish. 
https://www.geappliances.com/ge/heat-pump-hot-water-heater.htm