What is the most common type of boiler?

The most common type of boiler is a gas-fired, forced-air boiler. This type of boiler uses natural gas or propane to heat air, which is then circulated through a system of ducts and vents to provide heat to the home. Forced-air boilers are efficient, reliable, and relatively easy to install and maintain. They are also the most cost-effective option for most homeowners.