Technology advancements have changed the answer. It depends on what lighting system they use.
The old Incandescent Lamp 'light bulb' emits most of its energy consumption as heat, and would reduce the load on the heater.
However, a modern Compact Fluorescent Lamp or LED lighting system produces significantly less heat. This higher efficiency means that it would be wasting energy to leave it on.
Julia and Wayne heat their house during the winter with an electric heater. The
thermostat on the heater is set to 20°C and the thermostat is cycling on and off as it
keeps the room temperature stable. Julia walks out of the room leaving the lights on.
Wayne tells Julia that she is wasting electricity. Julia says that she’s not.
Who is right? Discuss
2 answers
I don't agree with what Graham's says about the more efficient lighting systems. All the energy produced by the lights is eventually going to heat the room (if you ignore the amount of light energy that leaves the room via the windows).
It doesn't matter whether you emit the energy in the infrared or the visible spectrum, it will all contribute toward heating the room.
It doesn't matter whether you emit the energy in the infrared or the visible spectrum, it will all contribute toward heating the room.