This is a 40 watt light bulb. If you leave it on all the time, it uses a kilowatt hour of power every day. And it is possible to use that to measure all forms of power consumption using this unit of light bulb. I started measuring everything around my house, around my office and I found some surprising things. First I plugged in a phone charger. It didn’t even register on this caloriemeter. It uses 100 of light bulbs worth of power. I don’t think the phone charger is gonna be our number 1 form of energy consumption. Just taking one hot bath everyday uses the same energy, same power of 5 light bulbs all the time nonstop. And I have been using steadily about 40 light bulbs worth of gas for heating, making hot air, hot water and that surprised me. Transport is one of the biggest forms of energy consuption. It uses about a third of our energy. If you drive an average car 50 kms a day, that corresponds to 40 light bulbs on all the time.