The boiler is activated when the thermostat in your home detects a reduction in temperature. When the boiler starts up, it generates heat using fuel, such as gas, propane, oil, or electricity. The water inside the boiler is heated, but it’s typically not heated to boiling temperatures as the name boiler suggests. Then, through radiators or radiant floor systems, heated water is distributed throughout your home, where it radiates heat to warm the air. The water returns to your boiler where it is warmed again and pumped back out to continue heating your home. This process continues until your thermostat signals that your home has reached the desired temperature, and the boiler will be turned off.