People are only just realising what a fridge's dial numbers really mean - and strangely enough it's not actually to do with the temperature, in Celsius or Fahrenheit.

They're a vital household appliance in every kitchen, but for decades people have used fridges to store vital foods like milk, fresh meat and vegetables without realising they may not be setting the fridge correctly at all.

The white goods item, whether it's an integrated fridge freezer, or just a freestanding fridge, will have a little white dial on the inside, usually at the top right near the door hinge, which is to set the temperature.

But it's not as simple as that. In fact, although changing the dial will indeed affect how cold the fridge is, the numbers marked on it do not actually refer to degrees C in most cases.

Reddit members explained the issue - the dial's numbers actually mean how powerful the fridge's chilling setting is. So higher numbers mean colder, not lower numbers.

One said: "Higher is colder... the numbers on the fridge's temperature dial indicate refrigerant power. The higher the number goes the colder the fridge will maintain. Setting it to 5 will make your fridge the coldest."

Some people will have mistakenly thought that 1 refers to 1C and is therefore colder, but that's not the case with most models on the market today.

It could mean your food goes off more quickly if you're not setting the right temperature, or it could lead to a build up of ice at the back of the fridge if you're setting it too cold.

Sarah Heaps, refrigeration expert at appliance retailer AO, explains it officially.

She says in AO's online guidance: "Most fridges have a temperature dial or setting knob which ranges from 1 to 5 or 1 to 9, depending on your model. As a rule of thumb, the higher the number the colder the temperature and conversely the lower numbers are the warmest settings.

"The ideal temperature for your fridge is between 3°C and 4°C. This range will keep your food safe and fresh without the worry of freezing it. Most people find that setting their fridge at around 3 on a 1-5 scale or 4-5 on a 1-9 scale keeps things at this temperature.

She added: "If your fridge is too warm then you can spot some signs quickly as perishable foods like your milk, eggs, fruit and vegetables can turn bad faster due to the exposed heat. You may also notice that droplets of water are beginning to form inside your fridge, which may indicate that your fridge is struggling to maintain a cooler temperature."