Not quite. If the roof were highly reflective and it's a clear sky, it would reflect sunlight (including infrared) back into space. Of course, we're talking about such minimal levels of power here compared to, say, heating a house in the winter that it's irrelevant.

It needs around 300 W to run Qwen 3.8-27b here, which is roughly eqivalent to me as a human walking around and doing basically anything other than sitting still.