How to Calculate your Energy Consumption

It's the flavour of the day but saving the planet is all very well unless you have no idea how to work out things like energy consumption. For many people, energy consumption simply means whether the gas and electric bills are higher than expected. This is how you can calculate the energy consumption of your electrical appliances:

1. Look for a plate on the equipment that says what the maximum power requirement is. It might be in Watts, KiloWatts (1000 Watts) or in Amps.
2. If it is in watts, divide it by 1000 to find out how many units (KiloWatt Hours) it will use when running at maximum power. For instance, your fridge says 250 Watts. Divided by 1000 is 0.25 or a quarter of a unit per hour at full power.
3. If it is in Amps, multiply it by 0.23 to get the kilowatts and kilowatts over the course of an hour makes units. e.g. A 3Kw tumble dryer will use a maximum of 3 units per hour.

If you do this for a range of items, you might be surprised that things like tumble dryers and electric showers use vast amounts of power compared to things like TVs and mobile phone chargers. You might not.

After you have these, you need to work out how much is actually used. This can be hard for things like fridges which are always switching on and off and for washing machines, which only use large amounts of power when heating the water inside. You have two options to work this out:

1. For things like TVs, work out how many hours per month you use it and then multiply this by the power consumption. e.g. a TV might use 0.1 units of power and you might use it for 40 hours per month = 4 units. Again you might be surprised that low power things when used frequently add up to a lot of power.
2. For items like fridges and washing machines, their usage might be found in the instruction manual or otherwise you can measure it with the electricity meter. With everything else switched off at the mains (you can leave your clocks plugged in!) read your electricity meter and then go out somewhere for a while - do not open your fridge or turn anything else on. If your washing machine, you must obviously wait until it finishes the cycle. After the cycle finishes or perhaps 2 hours, read the meter again. Most of this amount will be your appliance (some might be things that you have not switched off like clocks, chargers etc). Divide this amount by the number of hours you have watched it for (fridge) or simply use it as an amount per cycle for the washing machine and you can then look down your list and find out where you can make savings in electricity.

Bear in mind that a washing machine uses much more power on a hot wash than a cold one so if you regularly use a hot wash, measure that and measure a 40 degree wash too.
For most people I expect that lights being left on, washing machines and tumble dryers being used too often and a poor quality fridge are where most power savings come from. I can't imagine your children will be pleased if you suggest a maximum of 5 minutes of TV every day!!