Making use of energy – WJECWays to reduce heat loss

Heat energy can be transferred from areas of high energy to areas of lower energy by conduction, convection and radiation. Understanding how to control these processes helps reduce energy consumption.

Part ofPhysics (Single Science)Electricity, energy and waves

Ways to reduce heat loss

If heat loss can be reduced, less fuel is needed to heat the building and less carbon dioxide is released into the atmosphere, thus reducing the increase in greenhouse gases that lead to global warming. There are several different ways to reduce heat loss.

Simple ways

Simple ways to reduce heat loss include fitting carpets, curtains and draught excluders. It is even possible to fit reflective foil in the walls or on them.

Double glazing

Heat loss through windows can be reduced by using double glazing. These special windows have air or a vacuum between two panes of glass. If the double glazing has a vacuum there will be no conduction or convection. If the double glazing is made with air between the glass then convection is minimised because there is little room for the air to move. Air is a poor conductor so there will be very little heat loss by conduction.

Cavity wall insulation

Heat loss through walls can be reduced using cavity wall insulation. This involves blowing insulating material into the gap between the brick and the inside wall. The insulating material contains pockets of trapped air and therefore reduces conduction and convection. The fibres of the insulation prevent the trapped air from circulating and causing a convection current to be set up. Due to the fact that less heat is transferred to the outside wall, it also reduces convection on the outside of the building.

Diagram showing a cross-section of a wall. There is a layer of insulation between the outer wall and the inner wall.

Cavity wall insulation often has a layer of silver foil in order to reduce the heat lost by infrared radiation, by reflecting it back into the building.

Loft insulation

Heat loss through the roof can be reduced by laying loft insulation. This works in a similar way to cavity wall insulation.

Diagram showing a cross-section of a house's roof space. It shows an insulated loft and curved red arrows showing that heat cannot escape the room below through the ceiling because of the insulation.