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Energy per cooled liter
Energy-wise, chest freezers are the most economical type of freezers. Since they have sidewall insulation and are opened from the top, chest freezers can maintain their cold temperatures very well. Opening from the top reduces energy consumption per volume, especially when opening and closing the outer door of the unit on a regular basis. Less energy is lost when opening the outer door of a chest freezer compared to an upright freezer as no cold can literally fall out of the freezer.
Based on consumption values, this can be as the following:
The 570 L upright freezer needs 13.3 Wh/ day and liter of cooled volume whereas the 660 L chest freezer needs 12.3 Wh/ day and liter of cooled volume. Both units have similar wall insulation based on PU-foam and vacuum insulation panels as well as green cooling liquids.
A far lower but more long-term loss of cold air is the door gasket – which is always the weakest point of a ULT freezer’s insulation. As chest freezers have no vertical opening, no cold can leave the freezer via the gaskets as in an upright freezer.