The climate control in my (non-tesla fwiw) EV with a heat pump uses around 2kW when its going full-out. Anecdotally it also heats the cabin much faster than a space heater would.
Usually it's only pulling that much juice for the beginning of a drive and after a few minutes it reduces when it finds a steady-state.
2kW is about the same amount of juice that the drivetrain pulls when driving 35mph, so it can make a pretty big difference in the efficiency of shorter drives.
Sidenote: even though resistive heating is less efficient in heat per watt, using the heated seats is usually more efficient in terms of comfort per watt than heating the entire cabin
Usually it's only pulling that much juice for the beginning of a drive and after a few minutes it reduces when it finds a steady-state.
2kW is about the same amount of juice that the drivetrain pulls when driving 35mph, so it can make a pretty big difference in the efficiency of shorter drives.
Sidenote: even though resistive heating is less efficient in heat per watt, using the heated seats is usually more efficient in terms of comfort per watt than heating the entire cabin