Yeah, cold urban areas are going to be a bigger challenge. Someone in my old neighbor did drilled geothermal. It doesn’t take much space but you need a ground scan to make sure there isn’t anything problematic in the way.

For cities there is talk of effectively reviving steam heat loop systems except this time built around heat pumps. Basically using the existing natural gas right of ways to provide room temperature recirculating water from a centralized source. Denmark is experimenting doing this with waste heat from data centers and other industrial processes.