It’s not uncommon for the back of a fridge to form a layer of frost, due to water always collecting at the coldest point and freezing.  It can be avoided by opening the fridge as little as possible and for as short a time as possible to avoid the fridge having to work harder to cool down.  Also putting hot food in the fridge can add to this problem as it heats up the internal temperature of the fridge causing it to work harder.  A more serious issue might be that the seal on the fridge door is broken, and the fridge is constantly working overtime to keep the temperature down. In this case, it might be time for a new refrigerator altogether.  If it’s time to bid your fridge goodbye, take a look at our post on the Best Fridge Freezers Under £500 In The UK for some ideas.