This is our house. The second from right. See how two out of four walls are adjacent to a neighbor? Means heat doesn't spill out into the open air. The house is very well insulated so yes, it's warm. We have a fireplace, but never make a fire, since it's so warm anyhow. But recently, a beloved friend who lives in LA came to visit and she didn't think our house was warm at all.
So to answer your question: I think both. We're warm and the house is warm. Outside, it's currently