There are two common heaters that exist in normal homes other than fireplaces. These are boilers and furnaces. The difference is that a furnace heats up air while a boiler heats up water. A boiler gets its name because they use to heat water to a near boil to heat homes. In this video, you will learn more about how a boiler system works.
The first step in a boiler system is for a thermostat to call for heat. It does this by sending an electrical signal to the boiler which is often located in the basement.
The burner at the bottom of the boiler then heats up using the energy supplied by the fuel or electricity. This burner then transfers this energy to the water. This hot water is then piped throughout the home through things such as fan convectors, radiators, or radiant heat systems. These fixtures allow the heat from the water to escape into the home. This process also removes oxygen. Even so, boilers also have an expansion tank to stabilize pressure changes. As you can see, the basics of a boiler are really very simple. Hopefully this video has provided you some insight into how boilers work.