This applies to all plug in EVs. As far as I can tell they all quote their range figures running without any electrics other that the motors switched on. Lights, stereo, wipers, satnav, DVD player (OK probably not in a two seater), horn, electric windows, heater and air con are all going to knock chunks out of your range. OK so most of those also effect the range of an IC car, so it's something of a moot point. Things like your lights, satnav and stereo wouldn't add up to much anyway. The whole lot added together without the heating wouldn't even make 0.5KW.
However the one thing that doesn't affect an IC car's range is the heating. I've never really looked into it, but what is the heat output of a car heater on full blast? Surely it must run to at least a couple of KW. Presumably an EV is going to need an electric heater. So on a cold winters day you could expect the range of the typical EV to be reduced somewhat, as is the performance. Loosing 2KW is not the end of the world, but I'll bet performance car drivers will object. The loss of range may be more critical. Taking a well publicised car, the Tesla, you would be looking at a reduction in range of about 10 miles driving in chilly conditions.
Since most EVs seem to be driven by sanctimonous green activists can we expect to see them all driving around in full snow gear next winter?