Is it a boiler or a furnace?
Many homeowners may confuse these terms, but, there is an easy way to remember: a boiler uses hot water (think of "boiling" water) to heat your home, and a furnace uses warm air (also referred to as forced air).
A hydronic system uses water or steam to heat your home. In a hot water system, the boiler heats the water to approximately 180 degrees. A circulator moves the water through the pipes that lead to baseboard heaters, radiators or radiant tubing.
In a steam system, the boiler turns the water into steam, which then rises through the pipes to radiators.
A warm air system uses a furnace to deliver the heat throughout the home. The air is heated in the furnace and a blower forces it into a duct system. The warm air is then released into your home, through vents or registers in your walls, ceilings or floors.