Is the water heater just in time? I’m guessing not because the heat pump would need some time to startup? Also is it 120V? I have a gas JIT hot water heater that will need to be replaced in a few years and I’m wondering where the tech is at right now.

No, it tries to maintain a full tank of hot water, like other 50 gallon water heaters. I think the just-in-time ones are under your sink. They have their advantages too, I guess.

It's 240v, uses a double circuit breaker, so you need to check your circuit breaker panel to make sure you have two places open.

Our utility company had a special deal--we paid only $240 for the heater, although installation was around $3k (they brought an electrician to run the wire from the panel).