If you've got a good sleeping bag, -2 C isn't that bad. I've spent the night with those temperatures in the high country of New Zealand. I know people that have spent the night in -15 C temperatures.
That may be OK for sleeping but it is very hard to work. I spent a couple of Winters coding without heating with indoor temperatures around 12 Celsius and it was very hard. I wore mittens, bubble hat, a blanket and even an electric foot warmer and still had to stop working and walk a bit every now and then to warm up.