You can get spacer heaters, but in terms of electricity usage tank heaters will be cheaper to run.I am looking for info on a system or method of heating several tanks with one source of heat. I have seven tanks now and I have become aware that heaters are a big part of the electricity bill of running the fishroom, especially here in Maine. Any ideas ? Thanks. BBF
Gerald is right, all energy ends up as heat eventually.Electric heat costs the same to produce whether the heating device is an aquarium heater, heat tape, or heating pad. The rate of heat loss from the water to the surrounding room is what ultimately determines the electric cost. Put all the tanks side-by-side, insulate around them, and cover them as completely as you can to reduce heat loss and thus electric bill.