Three capacities
- Gross volume: the space inside the liner with the door closed, as if the cabinet were an empty box. It is the largest number and the one most often quoted.
- Net or storage volume: gross volume minus space taken by parts you cannot store in, such as the evaporator housing, fan, air ducts and areas that are not kept in the temperature band. Test standards for some appliance types define how this is measured.
- Usable volume: what your containers actually fill once shelf thickness, shelf pitch, gaps for air and the shape of pans, crates and bottles are counted. No brochure gives this; you work it out.
Worked example: a two-door upright
Assumptions: internal dimensions 1,340 × 700 × 1,900 mm; about 12% of the box taken by the evaporator housing, fans and air duct; two sections each with 6 shelf levels taking 2 GN 1/1 pans of 150 mm depth per level; pans filled to about 80% of their nominal volume.
| Capacity | Working | Litres | Share of gross |
|---|---|---|---|
| Gross | 134 × 70 × 190 cm ÷ 1,000 | 1,782 | 100% |
| Net (estimated) | 1,782 × 0.88 | 1,568 | 88% |
| Pan volume | 24 pans × 25.8 L (530 × 325 × 150 mm nominal) | 620 | 35% |
| Food actually held | 620 × 0.8 | about 496 | 28% |
Why usable capacity is so much lower
The biggest losses are between shelves. A 150 mm pan needs a shelf pitch well above 150 mm so staff can slide it in and out, and the shelf itself has thickness. Air needs space to circulate between pans and walls. Real GN pans also taper and have rounded corners, so their actual capacity is below the nominal box size.
This is not a flaw in the cabinet. It is how refrigerated storage works. It simply means the litre figure is the wrong basis for sizing.
Other formats lose space differently
- Chest freezers lose space to the compressor step and to the load line; in our tub-packing example, only about 53% of gross volume held ice cream.
- Visi coolers lose space between round bottles; 210 bottles of 600 ml is 126 L of drinks in a cooler rated at several hundred litres.
- Undercounters lose a large share to the compressor compartment, which is why their usable space is small for their footprint.
- Display cases are sized by deck area, not volume; litres are almost meaningless for them.
How to compare cabinets properly
Ask each supplier for internal shelf dimensions, the number of shelf levels and the adjustable pitch range, and whether the quoted capacity is gross or net. Then count how many of your containers fit per shelf and how many levels your tallest container allows. Compare cabinets on positions for your containers, and on running cost per position, rather than on litres.
Checking a cabinet yourself in the showroom
- Take a tape measure and one of your own containers, such as your most-used GN pan or crate.
- Measure the clear shelf width and depth inside the side walls and in front of the rear air duct, not the outside of the cabinet.
- Measure the lowest and highest usable shelf positions and the pitch steps of the shelf supports.
- Count how many of your containers fit per shelf and how many levels fit at your container's height plus a finger gap.
- Multiply, then compare that figure across cabinets. Ten minutes of measuring is worth more than any capacity claim.
Frequently asked questions
- Is a higher litre rating always better value?
- Not necessarily. A cabinet with fewer litres but shelves that suit your containers can hold more of what you actually store. Count positions, not litres.
- How do I find out whether a figure is gross or net?
- Ask the supplier directly, and check the spec sheet wording. If a figure is close to the internal width × depth × height, it is gross. Labelled appliances under a test standard usually state which volume is shown.
- Does usable capacity change with shelf position?
- Yes. Setting shelf pitch to suit your tallest container on every level wastes space. Set lower pitch for shallow pans and wider pitch only where tall items go, and you gain levels.
