Model 3 users report using about 240 to 300 watt-hours per mile. So I think that means a 1KW heater for an hour is equivalent to about 3 or 4 miles of range. S

Model 3 users report using about 240 to 300 watt-hours per mile. So I think that means a 1KW heater for an hour is equivalent to about 3 or 4 miles of range. So a 1KW heaster for 4 hours would lose you 16 miles of range.