Where's an old wife when you need one?

Tomorrow the boys go back to school. And as if to complement the change in domestic regime, as I fussed about the kitchen this morning it seemed a tad parky.

Now what to do? The sun is still shining, and at day's end last night was a vision of topless manhood catching the last rays of the day painting an exterior wall.

But somewhere in my being is an odd notion, I suspect inserted by a young wife whose physiology is more attuned to a daily 32 degrees, that old houses with thick stone walls need to be warmed from within while it's still clement to keep roasty-toasty come winter. Miss the window and you are in a chill zone throughout.

Thing is, that hardly tallies with the eco-cred. Or the drop a degree brigade.

Now I know what our power suppliers think, because already I am seeing banners a) telling me to pop the rads on, but b) do it with their tariff... to save the environment.

I just wondered if there was any actual science on the matter out there?