gasboilers

Gas boilers are heating appliances that burn natural gas or liquefied petroleum gas (LPG) to heat water for space heating and domestic hot water. In most systems, the heated water circulates through radiators, underfloor heating, or a storage cylinder. Gas boilers are common in residential and small commercial buildings due to their ability to provide reliable heat with comparatively low fuel costs.

There are several configurations. Condensing boilers recover additional heat from exhaust gases and achieve higher efficiency than non-condensing models. Combi (combination) boilers provide both space heating and domestic hot water on demand, eliminating a separate hot water cylinder. System boilers require a hot water cylinder but no feed-and-expansion tank, while regular (open vent) boilers use both a cylinder and a tank. All types vent combustion gases through a flue to the outside, and the exact setup depends on local codes and the fuel supply.

Components typically include a gas burner, a heat exchanger, a circulation pump, expansion vessel, pressure relief valve, and controls such as a thermostat or boiler clock. Condensing models use a condensate drain and may include weather compensation or outdoor reset controls to improve efficiency.

Safety and maintenance considerations are central. Gas boilers produce carbon monoxide if venting is faulty or poorly combusted, so proper installation, ventilation, and CO detectors are essential. Annual servicing, checking flue integrity, pressure, and burner operation, and addressing scale or sludge in the system help sustain efficiency and safety.

Efficiency and emissions: modern condensing boilers commonly achieve high energy efficiency, with lower NOx emissions than older designs. In many regions they are installed as part of energy-safety and building-code requirements, often with incentives for higher efficiency. Alternatives include heat pumps and electric boilers.