Freezers with ice build up operate inefficiently. If this is the case with some of your freezers, first of all determine whether there is a problem with the door seals which are often the cause of ice build up. If ice is building up quickly because of poor seals then replace the seals. Otherwise, if the freezer has been on for a long time and ice has built up gradually, schedule a time to defrost the freezer. This can be done just before a holiday when it is efficient to defrost the freezer and leave it off until the end of a holiday.