You should be able to describe how heat energy is lost from buildings and to explain how these losses can be reduced. Take a look at this diagram showing heat loss from a house. conduction The transfer of heat energy through a material – without the material itself moving. through the walls, floor, roof and windows. It is also transferred from homes by
convection The transfer of heat energy through a moving liquid or gas. For example, cold air can enter the house through gaps in doors and windows, and convection currents can transfer heat energy in the loft to the roof tiles.
Heat energy also leaves the house by radiation through the walls, roof and windows. There are some simple ways to reduce heat loss, including fitting carpets, curtains and draught excluders. Heat loss through windows can be reduced using double glazing. There may be air or a vacuum A volume that contains no matter – space is almost a vacuum. between the two panes of glass. Air is a poor conductor of heat, while a vacuum can only transfer heat energy by radiation. 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, which reduces the heat loss by conduction. The material also prevents air circulating inside the cavity, therefore reducing heat loss by convection. Heat loss through the roof can be reduced by laying loft insulation. This works in a similar way to cavity wall insulation. Loft insulation is used to conserve Heat Energy in the home and prevent loss of heat and excessive use of fuel. Heat energy causes convection currents in.
Loft insulation is used to conserve Heat Energy in the home and prevent loss of heat and excessive use of fuel. Heat energy causes convection currents in the air within the house, Convection causes the warmer air to rise and, by doing so the warmer air can escape by conduction through the ceiling into the loft. With no insulation on the floor of the loft the heat will continue to rise and dissipate through the roof and eaves of the house thereby losing and wasting heat and thereby wasting fuel.