Gas boilers are heating systems that use natural gas or propane to generate heat for residential or commercial spaces. They work by burning gas to heat water, which is then circulated through pipes to radiators or underfloor heating systems. This process provides warmth and hot water for various needs, such as bathing and cooking. These boilers are popular due to their efficiency and relatively low operating costs compared to other heating methods. Regular maintenance is essential to ensure safety and optimal performance, and they often require proper ventilation to prevent the buildup of harmful gases like carbon monoxide.