Electronic Shelf Labels for Freezers and Chilled Aisles

A standard electronic shelf label is built for the sales floor, not for a freezer wall. Cold-rated variants state operation down to -25 °C, but low temperatures slow the e-paper refresh, shorten battery life and invite condensation and frost. What settles the purchase is a trial in your own cabinet, not the datasheet.

Which temperature range each family states

Manufacturers do not sell “the label” but families of them. In SoluM’s November 2024 specification sheet, the standard range is rated 0 to 40 °C. The freezer variants are rated -25 to 0 °C. This page goes deeper into the cold-variant section of the technical guide to shelf labels; here we stay with what changes once the cabinet is below zero.

Family	Stated range	Stated battery life	Source
SoluM standard	0 to 40 °C	Over 5 years (one battery) or over 10 (two batteries), at 2 updates a day	Sheet of 28 Nov 2024
SoluM freezer, 2.2”	-25 to 0 °C	Over 5 years, 2 CR2450 batteries, 1 update a day	Same sheet
Opticon SE-214F	From -25 °C upwards	Up to 5 years, low-temperature lithium battery	Manufacturer page

Two details deserve a close read.

First, the freezer range stops at 0 °C. That means it was designed for cold, not for a cabinet that swings between a chiller and the shop floor. If the label sits on the edge of an open multideck, where the screen temperature rises and falls with the airflow, the range is a guide and not a guarantee.

Second, the battery figures are not uniform. SoluM’s commercial page for its Newton Pro Freezer range talks about “more than 10 years”, while the specification sheet from the same year gives more than 5 years for the 2.2” model at one update a day. We cannot tell whether that reflects different models or different measurement conditions, which is why the figure to demand is the one written into the quote, together with the daily updates and the temperature it refers to.

Why refresh gets slower below zero

E-paper moves pigmented particles through a fluid to form the image (the basic mechanics are in the entry on e-paper). When it is cold the fluid becomes more viscous, the particles move more slowly, and the controller needs longer, more elaborate signals to reach full contrast. Display maker Orient Display puts it as: e-paper is very sensitive to temperature, and cold calls for more complex compensation algorithms.

The patent literature shows the ink maker’s side of it. An E Ink patent application on driving bistable displays describes temperature compensation through look-up tables of waveforms stored for different temperature intervals, and warns that the temperature that matters is that of the material at each pixel, which can differ substantially from the air around it. In a cabinet whose door keeps opening and closing, that gap is not theoretical. A second patent, now also held by E Ink, aims to compensate without a sensor, because response speed shifts with temperature, from batch to batch and as the material ages.

In store terms, three consequences:

1. A price change takes longer to show. For a single price it hardly matters, but it is noticeable in bulk updates, especially in colour. We found no published refresh time for freezer variants, so it is a figure you have to ask for.
2. The image may have lower contrast or leave traces of the previous one. This is typical of a waveform badly tuned to the cold. When testing a model, change the same price several times and look at the screen up close.
3. Each refresh uses more energy. A longer signal draws more. That is the link to the battery, covered next.

This sensitivity is also why comparisons between e-paper and LCD in the cold are not symmetrical: neither technology comes out unscathed, but they fail differently.

The battery, the most overlooked link

At room temperature a lithium coin cell is an unremarkable part. In a freezer it is the limiting one. Every cell has its own operating range. As an example, the datasheet of a CR2450 from a cell manufacturer gives -20 to +60 °C, which is less cold than a label rated to -25 °C claims to handle. We do not know which cell each model uses, and Opticon’s freezer labels specify a low-temperature lithium battery, so nothing can be concluded about whether the others have a higher or lower limit. What you can ask is: which cell is it, and what minimum temperature does its maker guarantee?

Usable capacity also drops in the cold. Manufacturers acknowledge this without quantifying it: life falls with low temperatures and with frequent updates. The method for translating the datasheet figure to your store is in the article on label batteries. For a frozen-food wall the practical idea is to budget a battery swap earlier than the datasheet suggests, and to check that changing them does not mean taking down the whole rail.

Condensation, frost and moisture

This is the most likely failure and the least documented. Condensation appears when warmer, humid air meets a cold surface. In a store that happens when a freezer door is opened on a summer day, or when a label moves from a cold zone to a mild one. Water on the screen does not damage the ink, but it makes it unreadable until it evaporates. If it freezes, the frost can last for hours.

What the datasheets say:

• Opticon states that its SE-214F label resists moisture and frost build-up and can be read through a layer of frost. It publishes no ingress-protection rating.
• SoluM gives its freezer range an IP68 dust and water rating. IP68 describes how sealed the housing is; it says nothing about how legible the screen stays when it fogs.

These are supplier claims, with no independent testing, and none of them quantifies screen behaviour under condensation. The consequence is one of method: the most useful test is not a lab but the most demanding cabinet in your store. Note what happens after repeated door openings at peak hour, after a defrost cycle and after a weekend.

Where the label goes

Mounting depends on the type of cabinet.

Shelf rail in an open multideck or walk-in. This is the best-solved case. Opticon says its model fits dedicated shelf rails and is compatible with the most common shelving systems. What the datasheets lack is compatibility with your specific cabinet, which you confirm with a sample on your own shelving.

Glass door. There is no standard solution documented in the public datasheets we reviewed. A door is a cold surface, opened often, prone to fogging and in full view of the customer. Questions to ask: which mount the supplier proposes for glass (adhesive, magnet, inside rail, frame), which adhesive withstands cold and moisture without leaving residue, and whether the label is read from inside or outside the glass. Two risks the label cannot solve: glare from the glass on a screen with no backlight, and the difficulty of replacing a battery on a glued-on door label.

Chest freezer or island. The price sits on the rim of the chest, where the label takes knocks and condensation. Ask about rim mounts and impact resistance.

Radio suffers in refrigeration, too

A freezer cabinet is an insulated metal box with coated glass doors. Gateways mounted on the ceiling of the sales floor may not reach labels inside, or reach them with a heavily attenuated signal. The effect shows up not in the label datasheet but in the gateway’s, and in your floor plan. How to size them around freezers and metal shelving is covered in the article on gateways and access points. In the cold trial, measure coverage with the doors closed and the cabinet full.

Checklist for a cold trial

1. Ask for the datasheet of the exact model and check that the temperature range covers the real minimum and maximum of your cabinet (measure with a data logger, not the thermostat).
2. Ask about the battery: type, minimum temperature guaranteed by its maker, and life at your daily update count at that temperature.
3. Time the refresh in the cold, in black and white and, if relevant, in colour. Repeat the same change at least ten times.
4. Provoke condensation: open and close the door for an hour of peak footfall and photograph the label every ten minutes.
5. Test a defrost cycle and a full weekend.
6. Measure the radio with the cabinet full and the door closed.
7. Check the battery swap: how long it takes and whether anything has to be taken down.
8. Set a written acceptance criterion before you start, for example “no label unreadable for more than X minutes” (you set the threshold, not the supplier).

If the pilot covers cold only, it makes sense to fold it into a wider pilot project rather than buy a whole family on the strength of a one-week test.

When the cold-rated label is not the answer

In some stores it is more reasonable not to fit electronic labels on part of the cold chain: walls with glass doors that fog all day, very low-volume frozen lines, or lines with few price changes a year. There, a paper label or edge signage may be better, and the saving from an electronic label does not offset the risk of illegibility. To see how cold fits into a supermarket as a whole, with its markdowns on short-dated goods and its pricing rules, there is the supermarkets page.

Summary

Cold does not rule out electronic shelf labels, but it forces you to get three things right: a freezer-specific family, a battery guaranteed at that temperature and a real trial that includes condensation and radio. Every figure on this page comes from the supplier, without independent testing, and was checked on 9 November 2026.