Appliances Freezers: Keep your freezer at -18°C. For every degree below that, your freezer will use 2% more electricity. A full freezer operates more efficiently than an empty one. Ensure the door seal is tight and secure. Keep the back and underneath dust-free with regular vacuuming. Maintain a space of 5cm around your freezer so heat will be able to circulate away from the compressor and condensing coil. When buying a new freezer, look for a smaller chest freezer or an ENERGY STAR qualified model. More Defrost and clean your freezer annually or when the ice build up on the insides of the unit is more than ¼ inch.