heater

A heater is a device that converts energy into heat to raise the temperature of air, water, or other materials. Heaters are used for space heating, domestic hot water, and various industrial processes, and they transfer heat by convection, conduction, or radiation.

Common categories include space heaters, central heating systems, and water heaters. Space heaters are standalone units designed to warm a local area and may operate on electricity, natural gas, propane, or kerosene. Central heating systems provide whole-building warmth through furnaces or boilers that burn fuels or use electricity or heat pumps. Water heaters store or generate hot water for taps, showers, and appliances, using electric resistance, gas, oil, or solar thermal.

Efficiency is measured with different metrics: AFUE for furnaces and boilers, COP or HSPF for heat pumps, and energy factor or UEF for water heaters. Modern units often use condensing technology or variable-speed operation to improve efficiency.

Safety concerns include carbon monoxide risks from combustion appliances, fire hazards from improper installation or placement, and burns from hot surfaces. Proper venting, adequate clearance, detectors, and regular maintenance are advised.

Environmental and energy considerations depend on the energy source and efficiency. Electric heaters powered by low-emission grids can reduce emissions, while high-efficiency gas furnaces and heat pumps are common in many climates. Regular servicing helps maintain performance and safety.