The use of water as a heat transfer medium is known as hydronics. Water is heated and transported throughout the home using piping, the heat is then transferred to the surrounding air using radiators that may be mounted on walls or installed within the floor, also known as in floor radiant heating.
Most modern hot water heating systems have a circulation pump to assist in moving the hot water through the distribution system as opposed to older gravity-fed systems. They can also be “zoned” using zone valves which enables the homeowner to control the climate in different areas of the home as opposed to having one temperature setting for the whole home.
Some units offer as much as 90% efficient meaning they convert a full 90% of your fuel into usable heat. Most modern units are made with cast-aluminum heat exchangers as opposed to the conventional cast iron exchangers. Heat transfer occurs faster with the newer exchangers meaning heat is delivered to the home more efficiently.
These systems are a great option for homeowners looking to replace their out of date oil boilers and are easily installed. Some units are wall mountable and can give you back quite a bit of space.