the Rest of the House is always Cold come Winter.
bbrrrbecause there is zero insulation.
So we insulate. The ceiling with Fiberglass Batt.
We use some Spray Foam for the walls.
The walls were old foundation walls made of stone and brittle lime mortar. The upper part of the wall was all new with 2"x8" lumber. Living on the edge of the city and near water. Mice love the old lime mortar (easy to tunnel through) and the fiberglass insulation that was in the original kitchen was home to many nests. The 1" to 2" of foam sprayed on the exterior walls helped to insulate and seal out varmint and zero drafts. (ahhh...)
Run...I'm foamin' everything!