GCSE PHYSICS - The Cost-effectiveness of Insulating Buildings

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The Cost-effectiveness of Insulating Buildings.

Of the methods used to insulate buildings, some
are more effective than others. Cavity wall insulation will
save more energy than hot water tank insulation
but it is more expensive to install. We can calculate the
cost-effectiveness of building insulation by looking
at the initial cost and the annual saving (yearly saving).

For example, cavity wall insulation might cost £600
and provide an annual saving of £60.
At this rate, it will be 10 years before any money is saved.
The amount of time before money is saved is called
the pay-back time.
After 10 years there is a real saving of £60 per year.

Draught proofing is relatively inexpensive.
The initial cost may be £50 with an annual saving of £50.
The pay-back time is just one year because
the saving in the first year pays for the draught proofing.
After 10 years there is a saving of (10 x 50) - 50 pounds
(this is 10 years savings minus the initial cost)
(10 x 50) - 50 = £450.

Double glazing is relatively expensive and it may take
40 or 50 years before the annual saving covers the
initial cost. However double glazing also reduces
the amount of noise entering (or leaving) a building.

Cost-effectiveness is not the only consideration in
deciding the type of insulation used for buildings.
Any insulation makes the building more energy efficient.
Using less energy (conserving energy) has an
environmental benefit and may reduce pollution
and conserve fossil fuels. Conserving energy
is not the same as the "conservation of energy".

Cost-effectiveness is not the same as efficiency.

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