A mini-boiler is a smaller-than-average hydronic system that heats a space using either heated water or steam. Mini-boilers are commonly used for heating apartments, garages, animal barns and shops. They can also heat entire homes if one boiler is placed on each story.
A mini-boiler that utilizes a hot water system heats water to about 180 degrees Fahrenheit and then directs the heated water to the radiators or baseboard heaters through the installed piping. A steam system, on the other hand, heats the water until it turns into steam. The steam is then able to rise through the piping. An alternative option to a boiler is a furnace, which utilizes warm air rather than water to produce heat.