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1. Loft insulation, cavity wall insulation, hot
water tank jacket, draught-proofing and curtains
are good heat insulators. They
reduce heat transfer by convection because they
have trapped
air in them and air is a good heat insulator.
2. Heat
travels by radiation through a double glazed
window that has a vacuum between the two
panes of glass.
3. Payback
time (years) = Cost of installation / Annual saving
4.
|
Type of insulation |
Cost
(£) |
Annual
saving (£) |
Payback
time |
|
Double glazing |
5000 |
50 |
100
years! |
|
Loft insulation |
300 |
60 |
5
years |
|
Cavity wall insulation |
600 |
100 |
6
years |
|
Draught-proofing |
50 |
50 |
1
year |
a) The type of heat insulation that pays for itself quickly is
draught-proofing.
b) Double glazing is not a very cost effective method of heat insulation in a
house as it has the
longest payback time.
c) The most effective method of heat insulation is cavity wall insulation
because it saves the most
money each year.
5. The
advantages of saving energy are:
a) It saves money.
b) Burning less fossil fuels causes less pollution (less damage to the
environment).
c) Reserves of fossil fuels are not use up too quickly.
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