 But if you want to save some money, there's no reason not to put the electric water heater in as long as it's sized properly and it is on a timer because, of course, you only want that to run when you have to. Water heaters are dumb. They heat the water 24-7 whether you use it or not. So you want to make sure that it's properly insulated and the timer is set up so it's not running all night long when you don't really need it running.