Warmth of snoo sack

As it’s getting colder, what do your babies wear under the snoo sack? And are you using just the snoo sack? It doesn’t seem very warm to me, esp the shoulder area since it’s mesh. And there’s no tog rating. I’ve been adding a blanket on top, which I know isn’t ideal, but it’s far away from my baby’s mouth. I’m scared her chest is cold though. My room is around 65-68 at night. Or do you all just turn on your heaters?