Is this enough for a whole house?

Usually not. It is a compact single-phase electric unit best suited to one fixture or a small apartment. Whole-home electric tankless needs much higher power draw and often multiple units.

What electrical setup does it need?

It runs on single-phase power and needs a dedicated circuit sized to its draw, installed by a licensed electrician. It does not support three-phase supply.

Can it replace a tank water heater?

Yes, if the circuit and plumbing can support it. You gain wall space and skip standby losses, but you lose the stored hot water a tank provides during heavy simultaneous use.

Where can it be mounted?

It is designed for wall mounting and takes up about 10 by 15 inches with a shallow 3.7-inch depth. Check clearance and venting rules for your space before installing.

Does it work with hard water?

It will run, but scale can build on the heating element and cut performance. Flush or descale it periodically, or add a filter, if your water is hard.