What type of gas is primarily used in residential heating systems?

Natural gas is the primary fuel used in residential heating systems due to its wide availability, efficiency, and cost-effectiveness. It is delivered through an extensive pipeline infrastructure that makes it readily accessible in many urban and suburban areas. Natural gas burns cleaner than other fossil fuels, producing fewer pollutants and greenhouse gases when used for heating, which makes it an environmentally friendly choice among common heating options.

Additionally, many modern heating appliances, such as furnaces and boilers, are specifically designed to operate efficiently with natural gas. This fuel type also has a high energy content, allowing for effective heating at relatively lower costs compared to other fuels. While propane is also used in residential heating, especially in rural areas where natural gas isn't available, natural gas remains the most prevalent choice overall. The other options, such as coal gas and compressed air, are not typically utilized for residential heating purposes in contemporary systems.