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1. Using energy-saving bulbs is more efficient than normal bulbs because they transforms more
electricity into light and waste less heat compared to normal bulbs.
2. Payback
time (years) = Cost of installation / Annual saving
3.
|
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.
d) How Science Works
The type of
insulation is a categoric
variable.
4. 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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