I think I saw you mention that in your entry on it, and I know what you mean: it's definitely not warm in the sense of coziness. His situation in the house definitely seems chilly.

But I think I didn't find the sense of isolation as lonely as you did, which is maybe why I was able to read more warmth (in the sense of emotional warmth, not physical warmth) into it. I read him as being very caught up in his daily life--encountering the albatross, visiting the dead, noticing a leaf--and so I didn't experience vicarious loneliness. ... I think maybe Susanna Clarke intended a reading closer to what you experienced: I think maybe she wanted readers to see/understand that the narrator was in a lonely, desolate situation even if he himself didn't consciously perceive it as such. But it takes thinking about it for me to arrive at that.