Last edited 13 Nov 2020

Radiant heating

Heat transfer mechanisms include:

All bodies which are hotter than 0°K emit thermal radiation. They also absorb thermal radiation emitted by their surroundings. The difference in the total amount of radiation emitted and absorbed by a body at any given moment may result in a net heat transfer which will produce a change in the temperature of that body.

Solar radiation may be considered to include the ultra violet, visible and near or short wave infra-red radiation. However, most 'terrestrial' radiation, emitted by bodies at normal temperatures on earth, is far or long wave infra-red radiation.

Radiant heat transmits in straight lines, only warming surfaces that are ‘visible’ to the source. However, these surfaces in turn re-radiate heat and warm air adjacent to them by convection. This allows heat from a radiant source to distribute through a space. Because it is directly heating, rather than heating the air (as in convective heating), it can be more efficient, particularly in large spaces, in spaces with poor insulation or in unenclosed or semi-enclosed spaces.

Radiant heating systems tend either to be low-temperature systems spread over large surface areas, or high temperature localised systems.

Radiant heating systems include:

Some radiant heating systems also heat by convection, for example hot water radiators, often found in domestic buildings, radiate heat directly to their surroundings, but also draw air through heated elements resulting in convective heating.

Water-based systems such as underfloor heating can be used to provide cooling as well as heating. Radiant heating systems can incorporate renewable energy sources such as solar thermal panels, solar photovoltaics, ground source heat pumps, air source heat pumps and so on. They may also be used in combination with thermal mass and night-time purging.

Compared to other forms of heating, radiant heating (depending on the system used) can be:

Radiant heating also has less impact on air moisture content than other heating methods.

However, depending on the system adopted:

[edit] Related articles on Designing Buildings Wiki

Designing Buildings Anywhere

Get the Firefox add-on to access 20,000 definitions direct from any website

Find out more Accept cookies and
don't show me this again