Insulation techniques
1. cavity wall insulation:
heat is conducted through the walls. An air gap(cavity wall)
reduces the heat loss. Cavity wall insulation reduces it further.
The wool-like material used to insulate your home traps air in
between its fibres to create an ‘air matrix’. This is why cavity wall
insulation is much more effective at retaining heat than empty
cavity walls.
2. Double glazed window:
The two layers of glass
have a small air gap between them. The trapped air in the gap is
an insulator. It reduces the heat loss through conduction. The air
gap is too narrow to allow the air to circulate easily. This therefore
reduces the rate of heat transfer by convection.
The trapped air reduces the rate of heat loss through
the window by conduction and convection. The room in
the house therefore stays warmer for longer reducing heating
costs.
3. Loft 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.
4. Draught excluder:
Anything that blocks the cold air from travelling around your doors or
windows is an effective draught excluder. Remember that this is not
intended to be an insulator in the way that loft insulation or wall
insulation is. Insulation prevents heat from passing through it, whilst
draught excluders prevent cold or warm air from passing around it.
5. Under floor insulation
Heat is conducted into the ground. Many modern buildings have
under-floor insulation to reduce this heat loss
Heat loss from a badly insulated house is shown in the picture. Write down few ways to
reduce heat loss. Briefly describe how they work?