Fridge Power Consumption - Can the Star Rating be trusted?
The power consumption of domestic fridges is typically between 100 and 200 watts.
Over a full day they are likely to use around 1 to 2 kilowatt-hours (kWh). Old domestic refrigerators and commercial refrigerators consume much more.
The actual energy consumption of your fridge or freezer will depend on many factors. These include:
- Size – larger fridges generally use more electricity.
- Location – if the fridge is in a warm location (e.g. next to the oven) or if it is in a poorly ventilated area, the compressor will need to work harder.
- Usage – if the fridge door is opened frequently or held open, the compressor will need to work harder to keep things cool. Also, an empty fridge will work harder than a well-stocked fridge because more 'ccol air' is replaced with 'warm air' each time the door is opened.
- Temperature set point – the factory setting may keep the fridge cooler than is needed in your home. To store food safely, the temperature should be between 3 and 5 degrees Celsius. Check that your fridge and freezer temperatures are not unnecessarily cold with a thermometer like this.
- Age – older fridges are usually less energy efficient than newer fridges.
- Condition - check the seals around the door. If these are worn the fridge will be less efficient.
What about the star rating?
Energy efficiency 'star ratings' are a good buying guide, but because of the variable factors described above, the only way to know how much power your fridge is really consuming is to use a plug-in power meter. Some example power meters are shown at the bottom of this article.
Power consumption of our office fridge
To understand how much electricity your fridge is using over time it is best to keep the Power Meter plugged in and running over a 24-hour period. The fridge will not use power constantly and should only be drawing power when the compressor is running, and also when the door light comes on.
Using the Watts Clever Power Meter we found that the small fridge in our office uses between 90 and 100 Watts when the compressor is running.
We found that our fridge used 0.607 kilowatt-hours in a 24 hour period, which equates to around 221 kWh per year. The Power Meter showed that the fridge was drawing power for 6 hours and 10 minutes over that 24 hour period, or 25% duty, which is very energy efficient (a typical duty cycle for fridges is around 30%, or 8 hours per 24-hour period).
This is an office fridge so it's almost empty most of the time. We have also made sure there's at least a 10cm gap around all sides to allow air to move around the unit.
Electricity consumption of other fridges
I did the same test with my fridge at home and found that it uses about 1 kWh per day, which is typical for small units under 250 litres capacity.
Commercial refrigeration is more complex to measure but the opportunities for energy savings are greater. Some of the businesses for which we have completed business energy audits initially spent well over half of their electricity costs on refrigeration. In most cases, we were able to identify affordable cost-saving opportunities of 20-40%.
How much energy does your fridge use?
The easiest way to find out how much your refrigerators are using is to use a plug in power meter.
We sell three main options: the Reduction Revolution Power Meter is our most popular and cheapest option. The Watts Clever INPLUG allows you to monitor power usage from your phone or tablet. Finally, the Power Mate Lite is our highest accuracy option used by professional energy auditors.
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