Re:I just did this in my entire house. (Score 1)

That may be true on hot regions. But in Finland at wintertime we usually heat our houses. In that case light buld does not produse waste-heat, the more heat lights generate, the less we need to use other sources for heat up our houses. At summer AC is needed, but then again, who uses lights at summer when Sun does not set at all.

Remember that energy in an isolated system remains constant. Energy can be converted from one form to another, but it cannot be created or destroyed.