Heard an episode of CBC Radio's Ideas show on Hydrogen that had this fascinating aside (I'm paraphrasing):
During the 1970's oil shock buildings in Toronto turned out their lights to save energy, however many buildings had electricity from Hydro-electric resources and were heated via oil-fired generators. The net result was that turning off the lights made the buildings colder and it took more oil energy to heat them up again than if the lights were left on.
During the 1970's oil shock buildings in Toronto turned out their lights to save energy, however many buildings had electricity from Hydro-electric resources and were heated via oil-fired generators. The net result was that turning off the lights made the buildings colder and it took more oil energy to heat them up again than if the lights were left on.