A climate zone found in the middle latitudes, which span between the tropics and the polar regions of Earth.

The temperature difference from bottom to top of a volume of air or water which causes convection to occur.

Daily (diurnal) temperature range from maximum to minimum and back -measured in terms of variation from the mean (average).

See Heat Bridge.

The thermal or heat capacity of a body is the quantity of heat required to raise the temperature of a body by one degree.

By analogy with mechanics, a term to describe the dampening effect on temperature swings of thermal mass.

(Usually refers to high) thermal capacity in building materials. 

The effectiveness (and efficiency) or otherwise of a building in maintaining comfortable thermal conditions for its inhabitants.

The combined resistance (R) offered by a building element or assembly to heat transfer, including the effect of air spaces, reflectivity of surfaces and their condition; measured in m².K/W. Also known as the R-Value. It is the reciprocal of the Transmission Coefficient (ie 1/U-Value).

The rate at which heat is transmitted through a building element or assembly (U), combining radiation, conduction and convection, and including the effect of air spaces, and the reflectivity of surfaces and their condition; measured in W/m².K. Also known as the U-Value. It is the reciprocal of Thermal Resistance (ie 1/R-Value).

A continuously recording thermometer. The temperature recording is usually is made by the movement of pen connected to a bi-metallic spiral on graph paper on a rotating drum.

Publicity material and technical / construction / installation data provided by manufacturers and suppliers of building elements and materials. 

A measure of the heat flow to the interior of a building element due to variations in the external ‘driving’ temperature;  measured in  W/m².K

A material that allows light to pass through, allowing objects behind to be clearly seen.

A wall used to absorb thermal energy from incident sunlight and covered. It can be used to heat a space in cooler climates, or regulate temperatures in warm climates. Also known as a Mass Walls, Solar Wall, or Thermal Storage Wall.

A climatic zone largely falling in the equatorial or tropical zone. It is generally characterised by relatively warm and consistent temperatures throughout the year.