A boiler is essentially a big water heater and is used for heat only applications. There are two types of boilers - hot water and steam. In hot water boilers, the boiler heats the water and then circulates the water through the system to heat your home. Hot water boilers are the most efficient to operate. Steam boilers have to heat the water to boiling point and then circulate the steam through the system in the house to heat it. Steam boilers are less efficient because they have to heat the water to a higher temperature. We do perform service on residential boilers. We also install residential boilers - visit www.crownboilers.com.