How water should be extracted from the top of the container and cold water should be added to the bottom of the container. To replace this hot water, cold water should be added to the bottom of the tank, where it won't mix with any hot water that might still be present in the container. When a small amount of hot water is removed from the tank, cold water is added to the bottom of the tank. This water is then heated by the bottom heating element. Thus the bottom heating element runs more often and is more likely to burn out than the top heating element.
Insulation keeps heat from flowing out of the hot water and into the room.
The heat that leaks into the room may also overheat the room, requiring additional air conditioning. Since energy is conserved and can t accumulate forever inside the heater, it must leave somehow. This energy leaves as thermal energy in the hot water. When hot water flows out of the hot water heater, this energy leaves with it. Decompression sickness was first observed in workers preparing underwater foundations or caissons for bridges.