We keep our house heated to about 15 degrees and DD sleeps in a normal grow suit (thicker ones on really cold nights) and in her gro bag. She has a few diff togs but at the moment I've found the middle one (1.0) I think is doing fine. Her other winter ones are quilted so they are very cosy.

I also bought her a sheepskin on the weekend which takes the chill off the sheets and mattress. She only has a blanket over her when it's really cold but I find that she usually manages to get out of that anyway.

Remember they will prob cry when they're cold before they cry when they're hot so I would rather go on the cold side. So far she's been fine!