When energy shortages occur, magazine articles sometimes urge us to keep our homes at a constant temperature day and night to conserve fuel. They argue that when we turn down the heat at night, the walls, ceilings, and other areas cool off and must be reheated in the morning. So if we keep the temperature constant, these parts of the house will not cool off and will not have to be reheated. Does this argument make sense? Would we really save energy by following this advice?

Maintaining a constant temperature is compensating for every heat lost and gained from the system to the surroundings or vice versa. Here, the system is the house and the walls it is made of and the surroundings are everything outside the house. So, once the temperature of the house is set to the required temperature, then heat must be given to compensate for the loss of heat from the walls. Also, the temperature of the surroundings keeps on changing continuously. As the heat loss is dependent on the temperature difference if the surrounding temperature is higher the heat loss is higher too. This compensation is done using a heating device. Which will consume energy.

This process is extremely time and energy-consuming and is not practical. So, this argument is flawed when it comes to practical scenarios.