Well...I live someplace where -30C is a common occurrence in winter. I suggest:
Down or synthetic down quilt
flannel sheets
a warm coat
winter boots
Good gloves and mittens
WARM hat
Also, if it is really cold make sure you park your car with the engine facing away from the wind and the gas tank full so your tank doesn't freeze. it doesn't hurt to go out and start the car every few hours or so, that way the battery won't freeze out.
I wrap up in my sleeping bag in my apartment.
Sometimes I am forced to turn on those stupid electric baseboard heaters for like an hour and a half.
And when I go outside I have my long down coat,hat with built in earmuffs,scarf,gloves,and shearling lined boots.