Why cold appliances matter
Fridges and freezers are among the few appliances that run all day, every day. A small inefficiency therefore repeats thousands of times a year. That makes them worth getting right, even though none of the changes below is dramatic on its own.
Cold appliances work by moving heat out of the cabinet and releasing it into the room, usually through coils at the back or underneath. Anything that makes the cabinet warmer, makes the room warmer, or lets heat leak in will tend to make the compressor run for longer.
Placement
Where the appliance stands has a quiet but real effect.
- Keep it away from heat. A fridge next to a cooker, a boiler, a radiator or a sunny window has to work harder. If you have a choice, a cooler spot is generally better.
- Leave space for airflow. Most manufacturers specify a gap at the back and sides so the warm air can escape. Pushing the appliance tight against a wall or boxing it into a cupboard without ventilation can cause it to run longer. Check the manual for the recommended clearances.
- Keep the coils clean. Where the coils are exposed, dust can build up and make heat release less effective. Switching off and gently vacuuming them occasionally is a common recommendation, but follow your manual and unplug before any cleaning.
- Be cautious with unheated spaces. A second fridge or freezer in a garage or outbuilding may struggle in very cold or very hot conditions unless it is designed for them. Check what the manufacturer says about ambient temperature.
Temperature settings
Colder is not better beyond what food safety needs. Food safety guidance in many places suggests a fridge temperature of around 5 degrees Celsius or below and a freezer around minus 18 degrees Celsius. Setting the dial lower than that tends to use more energy without clear benefit, and can freeze salad and drinks.
A small fridge thermometer is cheap and more reliable than dial numbers, which are often arbitrary. Check the reading after the appliance has settled and adjust gradually, leaving time between changes. Food safety is the priority, so if you are unsure, ask the manufacturer or your local food safety guidance rather than raising the temperature to save energy.
How you use it
- Do not leave the door open. Decide what you want before opening. Each opening lets warm air in that the appliance then has to remove.
- Cool food before storing it. Putting hot dishes straight in raises the internal temperature. Letting food cool for a short time at room temperature first is often suggested, though leftovers should not be left out for long. If in doubt, follow food safety guidance.
- Pack sensibly. A reasonably full freezer holds its cold well because frozen items help each other stay cold. A fridge is different: if it is crammed, air cannot circulate, and some areas may not stay cold enough. Aim for loosely full rather than packed.
- Avoid overbuying. Cold storage space used for food that goes to waste is a double loss. Planning meals and understanding date labels helps you keep the appliance in good use and reduce food waste.
Seals
The rubber door seal, or gasket, keeps warm air out. If it is cracked, dirty or loose, the appliance may run longer than it should.
A common simple check is to close the door on a strip of paper and try to pull it out. If it slides out with no resistance in several places, the seal may not be gripping. Wiping the seal with warm soapy water can help if it is dirty or sticky, and many seals can be replaced as a spare part, which is often cheaper than replacing the appliance. Cleaning chemistry basics apply here: mild soap and water is usually enough, and strong cleaners can damage rubber.
Frost and defrosting
In a freezer without automatic defrost, frost builds up on the inside walls and acts as insulation between the cold surface and the food, making cooling less effective. Many manufacturers suggest defrosting when the layer reaches a few millimetres, though recommendations vary by model.
When defrosting:
- Unplug the appliance and move food somewhere cold, such as a cool box.
- Let the ice melt naturally, with towels to catch water.
- Never use sharp tools to scrape ice, because puncturing the cooling system can be dangerous and expensive.
- Dry the inside before restarting.
Frost-free models defrost automatically using a small heater, which uses a little energy but avoids heavy ice build-up. Neither type is clearly better in every home, so it comes down to the model and how it is used.
When the appliance itself is the problem
If a fridge or freezer is very old, noisy, constantly running, or has a failing compressor, it may be worth considering a replacement. Energy labels allow a rough comparison between models, and it helps to compare the labelled yearly energy use with your current appliance if you can find a figure. Remember that manufacturing has its own footprint, so a working appliance that is reasonably efficient is often best kept going with good care. When you do replace one, make sure the old one goes for proper recycling, since cooling systems can contain gases that need careful handling.
A brief once-over every few months, covering placement, temperature, seals and frost, tends to be enough to keep a cold appliance running as well as it can.