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
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.
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.
To determine who is right in this situation, we need to understand how electric heaters and thermostats work.
Electric heaters work by converting electrical energy into heat energy, which warms up the room. The thermostat on the heater acts as a control mechanism to maintain a specific temperature in the room. When the temperature falls below the set point (in this case, 20°C), the thermostat turns on the heater to generate heat and raise the temperature. Once the room reaches the set temperature, the thermostat turns the heater off. This cycle repeats as the temperature fluctuates.
Now, coming back to Julia and Wayne's situation, the lights being on has no direct impact on the functioning of the electric heater or its thermostat. The thermostat is solely responsible for monitoring and controlling the temperature. The lights consume a separate amount of electricity, and their usage does not directly affect the heater or its thermostat.
Therefore, in this case, Wayne is correct. Leaving the lights on does not waste electricity in the context of the electric heater or its thermostat.
However, it's worth mentioning that leaving the lights on unnecessarily does consume electricity and can contribute to higher overall energy consumption. Therefore, from an energy conservation standpoint, it is generally advisable to turn off lights and other electrical devices when they are not in use.