insulation

Some ways of insulating a house. One quarter of the heat energy loss in a house is lost through the roof. Insulating the loft with a fibre-fill material helps to reduce heat loss as the fibres trap air, which is a poor conductor of heat. Cavity wall insulation works in a similar way, as the insulation foam that fills the gap between the two walls also traps air. Double-glazed windows trap air between two panes of glass. Other preventive measures include using curtains and carpets and fitting draught excluders around doors and windows.

Process or material that prevents or reduces the flow of electricity, heat, or sound from one place to another.

Materials that are poor conductors of heat, such as glass, brick, water, or air, are good insulators. They play a vital role, for example, in keeping homes and people warm.

Electrical insulation makes use of materials such as rubber, PVC, and porcelain, which do not conduct electricity, to prevent a current from leaking from one conductor to another or down to the ground. Insulation is a vital safety measure that prevents electric currents from being conducted through people and causing electric shock.

Double insulation is a method of constructing electrical appliances that provides extra protection from electric shock, and renders the use of an earth wire unnecessary. In addition to the usual cable insulation, an appliance that meets the double insulation standard is totally enclosed in an insulating plastic body or structure so that there is no direct connection between any external metal parts and the internal electrical components.

Thermal or heat insulation makes use of insulating materials such as fibreglass to reduce the loss of heat through the roofs and walls of buildings. The U-value of an insulating layer is a measure of its ability to conduct heat - a material chosen as an insulator should therefore have a low U-value. Air trapped between the fibres of clothes acts as a thermal insulator, preventing loss of body warmth.