waterheating

Water heating is the process of raising water for domestic use, such as bathing, cooking, cleaning, and laundry, and it may also supply heated water for certain industrial processes. In homes, hot water is typically kept at around 120°F (49°C) to balance comfort and energy use. Energy sources include electricity, natural gas or propane, oil, solar energy, and heat pumps. Efficiency depends on insulation, the heat source, and how and when hot water is used.

Common systems include storage-tank heaters, tankless or on-demand units, solar water heating systems, and heat-pump water heaters. Storage-tank heaters store hot water in an insulated tank, usually sized from about 30 to 80 gallons (110 to 300 liters). Tankless systems heat water as it flows through a heat exchanger, reducing standing heat loss but with a limited flow rate. Solar water heaters use collectors to heat a heat-transfer fluid and a heat exchanger to warm the water, often with a backup heater. Heat-pump water heaters extract heat from the surrounding air to heat water, offering high efficiency. In larger facilities, district or centralized systems may supply hot water.

Operation varies by type. Storage heaters use a burner or electric element and a thermostat to maintain the setpoint, while Tankless units heat water only when needed. Solar systems rely on collectors and a heat exchanger, with a backup source for periods of low sun.

Safety and maintenance cover venting for gas units, pressure-relief valves, and temperature controls to prevent scalding. Regular maintenance includes flushing tanks to remove sediment, inspecting anode rods, and ensuring valves and controls function properly. Efficiency improvements come from proper sizing, good insulation, and the use of high-efficiency or hybrid systems.