Radiant heating systems involve supplying heat directly to the floor or to panels in the walls or ceiling of a house. The systems depend largely on radiant heat transfer: the delivery of heat directly from the hot surface to the people and objects in the room via the radiation of heat, which is also called infrared radiation. Radiant heating is the effect you feel when you can feel the warmth of a hot stovetop element from across the room.
When radiant heating is located in the floor, it is often called radiant floor heating or simply floor heating. Despite the name, radiant floor heating systems also depend heavily on convection, the natural circulation of heat within a room, caused by heat rising from the floor. Radiant floor heating systems are significantly different than the radiant panels used in walls and ceilings. For this reason, the following sections discuss radiant floor heat and radiant panels separately.
Types of Radiant Floor Heating Systems
There are three types of radiant floor heating systems.
Radiant Air Floors
Radiant air floor systems use a conventional furnace to pump the air through the floor. Because air cannot hold large amounts of heat, however, radiant air floors are seldom installed in residential applications.
Electric Radiant Floors
Electric radiant floors typically consist of electric cables built into the floor. Systems that feature mats of electrically conductive plastic are also available, and are mounted onto the subfloor below a floor covering such as tile.
Hot Water (Hydronic) Radiant Floors
Hydronic radiant floor systems pump heated water from a boiler through tubing laid in a pattern underneath the floor. In some systems, the temperature in each room is controlled by regulating the flow of hot water through each tubing loop. This is done by a system of zoning valves or pumps and thermostats.
Wall- and ceiling-mounted radiant panels are usually made of aluminum and can be heated with either electricity or with tubing that carries hot water, although the latter creates concerns about leakage in wall- or ceiling-mounted systems. The majority of commercially available radiant panels for homes are electrically heated. Unlike other types of radiant heating systems, radiant panels have very low heat capacity and have the quickest response time of any heating technology.
Visit the Energy Saver website for more information about radiant heating in homes.