The definition of a hot water system is quite simple. It is a system that uses heated water to provide warmth and comfort to a home or business. Hot water systems can be powered by electricity, gas, or solar energy, and are typically used to provide hot water for showers, baths, and other domestic uses. Hot water systems can also be used to provide heating for radiators, underfloor heating, and hot water cylinders. In addition, hot water systems can be used to provide hot water for industrial processes, such as in factories and laundries. Hot water systems are typically very efficient and cost-effective, and can be used to reduce energy costs.