The scientific study of the interrelations between living organisms and their environment, including both the physical and biotic factors, and emphasising both inter-species and intra-species relations; more specifically and more narrowly, the scientific study of the distribution and abundance of living organisms (ie exactly where they occur, and precisely how many there are), and any regular or irregular variations in distribution and abundance, followed by explanation of these phenomena in terms of the physical and biotic factors at work in the environment. 

A measure of how well a device or system works.

A measure of how well a device or system works in relation to the input of resources (eg energy) required.

The ratio of the heat emitted from a surface to that emitted under the same conditions by a ‘Black Body’.

The energy required in the industrial or other processes used to manufaacture building materials etc.

The two days of the year when day and night are of equal length,  21 March and 21 September.

Environmentally Sustainable Design.

A system of cooling produced by utilising the latent heat of vaporisation of water.

A fan which exhausts air (with its smells and water vapour) through a wall, window or ceiling from a space or building; often multi-speed. It is advisable that a ceiling exhaust fan be ducted through the roof space to the external air. (Compare with ceiling fan).