Energy efficiency

Energy is used throughout our daily lives, in our homes, the buildings we work in and on our roads. This energy may be used for cooking food, keeping us warm or powering electrical devices, but the vast majority is supplied to us through the use of fossil fuels such as coal, gas or oil.

The supplies of fossil fuels are reducing and the use of them often creates pollution in the form of carbon dioxide and other greenhouse gases which escape into our atmosphere and contribute to global warming.

As humans, we must ensure that we use the energy produced in the most efficient way. This may mean reducing the amount of energy we waste in order to maintain the supplies of fossil fuels for as long as possible and also reducing the financial costs to ourselves.

Being energy efficient requires us to use energy only when we need it and taking measures to reduce our wastage. By being energy efficient we can reduce the constant need for energy production, meaning that the amount of energy produced is only as high as is actually needed.

For example, it takes a lot of energy to keep our homes heated. Many people use a central heating system to heat their homes and most systems use gas. If the central heating was continually switched on, even when it wasn’t cold, we would use a lot of gas and it would cost a lot of money to us in the form of energy bills.

When we are heating our homes, as long as there is no transfer of heat energy to the outside, we can have the heating switched on for as long as it takes for the house to be at a comfortable temperature. We can then turn the heating off as the heat will remain in the house and keep the house warm.  This means that we would only pay for the energy needed to heat the house up.

When the heating is on, there will also be transfer of thermal energy to the surroundings. Thermal energy may be transferred to the outside environment of the house. This means that if this unwanted energy transfer is not reduced, you will not only be paying to heat up the house but also paying for the thermal energy transferred and used to heat up the surroundings of the house.

Examples of places in the house that unwanted energy transfer can occur through include:

• Open or poorly sealed windows and doors
• Roof
• Walls
• Floor

Being energy efficient also means considering ways in which these unwanted energy transfers can be prevented or reduced, meaning that we only pay for the energy we use rather than the energy wasted.

We can reduce thermal energy transfer from our homes in the following ways:

• Use of double glazing in the windows. There is a vacuum between the two panes of glass which prevents heat loss through conduction or convection as there are no particles to pass on the thermal energy through. Heat energy could still be transferred through radiation but this would only occur if infrared radiation was being emitted on a large scale.
• Use of draught excluders to cover any gaps through which heat energy could be transferred through convection.
• Carpets and curtains could be used to reduce energy transfer through convection.
• Cavity wall insulation could be used. The insulation between the two layers of brick prevents air circulation and therefore prevents heat loss through convection.
• Loft insulation prevents heat energy transfer through the roof through convection.

Although it is impossible to completely prevent all unwanted heat energy transfers, it is possible to reduce it using the above measures.