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How much energy does my freezer use?

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Hello there Ken,

Rather like understanding all the gobbledygook on an electricity bill, deciphering the electricity consumption of your freezer - or any household appliance - appears to be something the energy industry isn’t really interested in explaining to consumers.

Here’s the quick answer - look on your electricity bill and find the price you pay for one unit of electricity, multiply that by 340 and this will give you the rough cost of running your freezer for a year, as one unit of electricity is equivalent to one kWh.

If you’ve interested, this is an explanation of how we arrived at this calculation, why it’s not always straightforward and why what the manufacturers of white goods say should be taken with a pinch of salt.

What is the required voltage of my freezer?

Let’s deal with the simplest aspect first: the voltage, in this case the 240V AC.

Domestic mains supply voltage in the UK is 240 volts alternating current (AC), standardised in 1960. This basically means that your freezer will only work if plugged into a 240V socket (which is why Brits holidaying in the US, even though they have an adaptor plug, can never get things like hairdryers and shavers to work because the US voltage is 110V, which is insufficient to power most UK gadgets). So, the voltage is the “strength” of the power supply your freezer needs in order to work properly.

What is the wattage of my freezer?

So, (and we are talking in very crude terms here) if the power supply is measured in volts, consumption of that power and its conversion into energy is measured in watts (W), so your freezer consumes 100W a second. For billing purposes, energy consumption is measured in kilowatt hours (kWh) and so 100W converts to 0.1 kWh and, in theory, your freezer consumes 2.5kWh every 24 hours, or 876 kWh per year.

Now, that’s over twice what the manufacturer’s technical data says the freezer consumes (340kWh/year) and that’s why I added the caveat “in theory”. Although fridges and freezers run 24/7 and 365 days a year, once a freezer reaches the desired temperature, it goes into standby and only switches back on when its thermostat registers the internal temperature is rising and kicks back into life to cool it down and so only runs part of the 24 hrs.

Why does my freezer use more energy than the manufacturer said it would?

The manufacturer’s technical data will have been worked out while testing the freezer at what’s known as “ambient temperature” (basically the temperature created in the testing lab) and the higher the ambient temperature, the harder the freezer has to work to keep the chilled cabinet cold and so the more power it consumes. But some people keep freezers in the garage and some freezers are in the kitchen adjacent to the oven so, although the manufacturer’s technical data is correct in the testing lab, it will vary (sometimes considerably) depending on the environment the appliance is kept in.

Buying products carrying the Energy Saving Trust Recommended label will ensure that you are getting a more energy efficient product that will cost you less to run, as well as being more eco-friendly.

Compare energy prices with Energychoices.co.uk to make sure you are paying as little as possible to power your freezer, no matter how leccy-hungry it is.

Photo courtesy of Becoming Green.

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