I have my larger tanks in our garage, which is not insulated all that well so maintaining temp has been a problem. So, instead of cranking up the 900 watts of heaters, I pulled the dryer ventilation hosing out of the wall and am letting the excess hot air pour into the garage. Keeps the temp up in the garage by about 3-4 degrees per load. It's been a pretty effective energy saving trick (I thought I'd share) for us during these months when it hasn't been too cold. Tonight, though, it seems to be dropping faster, so here I'm trying to stay awake for do one more load of laundry to keep the fish warm. I think it might be time to insulate the tank again, and maybe invest in some insulation for garage. 