In order to manage your household expenses it can be useful to understand your energy bills. Knowing how gas and electricity suppliers calculate your bills can help you to manage your energy use so that it fits your budget.

The first things you need to understand are the units the energy suppliers use to measure usage. Your electricity charges are based on measuring the electricity you use in kilowatt-hours (kWh). Gas consumption is measured using cubic feet (cft). For the purposes of calculating your bill, most energy suppliers convert the cubic feet reading to its kilowatt-hours equivalent.

To understand a kilowatt-hour we first need to understand what a kilowatt is. A kilowatt is a measurement of energy consumption equivalent to 1000 watts (w). In turn one watt is equivalent to the consumption of one joule per second. Joules are the standard international measurement of energy.

A kilowatt-hour is an energy measurement describing how much energy a device running at 1000 watts (1kW) consumes in the space of one hour. Therefore a device which runs at 2kW would use 2 kWh in the space of one hour, and a device which runs at 500 watts would use half a kWh in the space of an hour. It may seem quite confusing to use the word hour in the title of the measurement, when it is not a measurement of time. It may however help to remember that miles per hour is a measurement of speed that works in a similar fashion.

To make it easier for people to compare their gas and electricity consumption, suppliers tend to convert the gas readings of cubic feet into kilowatt-hours. If you would like to perform this calculation first you need to convert the cubic feet to cubic meters by multiplying by 2.83. Then you need to multiple the result by the temperature and pressure figure you should find on your bill (typically around 1.02264). Next you should multiply this by the calorific value, also found on your bill (typically around 39.25). Finally you should divide this value by 3.6 to get the number of kilowatt-hours. If this seems a bit complicated you can make an approximate conversion by multiplying the number of cubic feet by 31.3.

Once you are confident of working out how much gas and electricity you have used you can then work out how much your bill should be by using information on your energy supplier's prices. Remember that not all gas and electricity suppliers charge the same prices and shopping around could help you to make significant savings.

Dave MacKinder writes for a digital marketing agency. This article has been commissioned by a client of said agency. This article is not designed to promote, but should be considered professional content.