For the past nine months dd (nearly 2) has refused any covers of any type or weight including sleeping bags, waking up if we dared put them on when sleeping. Suddenly she's started letting us put her duvet over her. So what else do we need once it's really cold - just a blanket on top of the duvet?
some children hate covers, my DD hates anything on her at night, we have only just got her to wear PJs or a nighty, often by morning they are gone,
she does have a micro fleece blanket(they feel very light,so don't bother her as much), and a feather duvet which she occasionally uses, we just put them beside her, she sometimes pulls them over her, but never for long,
her room is small and it has thermostatic controlled heating, but now she is older she turns it off,
just put it beside her and she will use it if she wants it.