How many temperature sensors does my kitchen actually need?
Last reviewed: 21 July 2026
"We put a sensor in the kitchen" sounds like coverage, right up until the under-bench fridge dies and the sensor two metres away in the coolroom never notices. The number of temperature sensors a kitchen needs is not a guess, and it is not one per room. This page gives you the rule, shows you how to walk your own fit-out and count, and works through a real example so you can size it yourself.
The rule: one sensor per independently-refrigerated unit
Every fridge, freezer and coolroom has its own compressor, its own door and its own thermostat. Each one can fail on its own while everything around it stays perfectly cold. So the count is not "how big is the kitchen", it is "how many separate things make their own cold air". One sensor each. A sensor can only report the box it is sitting in.
Why one sensor "for the kitchen" misses the fridge that dies
Cold units do not share fate. The coolroom can be humming along at 3°C while the under-bench fridge on the line quietly climbs to 12°C because its door seal went or its compressor packed it in. A single sensor in one unit tells you that one unit is fine. It tells you nothing about the other five. And the fridge that actually fails is almost never the one you happened to put the sensor in. That is the whole case for catching a failing fridge or coolroom before stock spoils: you can only catch the unit you are actually watching.
Walk your fit-out and count
Do not guess from memory. Walk the kitchen and physically count every unit that makes its own cold:
- Cool rooms (each one)
- Freezer rooms (each one)
- Under-bench and undercounter fridges
- Undercounter freezers
- Upright and reach-in fridges and freezers
- Display and prep fridges (bain-marie wells, salad and sandwich prep units)
- Standalone chest freezers, drinks fridges, dessert freezers
- Any bar fridge holding product you would have to throw out
If it plugs in and holds cold food, it is on the list. Count the physical boxes, not the rooms.
A worked example
Take a fairly ordinary commercial kitchen:
- 2 coolrooms
- 1 freezer room
- 3 under-bench fridges on the line
- 1 undercounter freezer
- 1 prep/sandwich fridge
- 1 drinks fridge at the pass
That is 9 independently-refrigerated units, so nine sensors, one per box. "A sensor for the kitchen" would have covered one of those nine and left the other eight blind. Eight out of nine is exactly where the surprise write-off comes from.
What doesn't need its own sensor
- A single coolroom with a shelf or internal run off the same box is still one air space, one sensor (unless it is genuinely a separate compressor).
- Dry stores, spare empty units holding no product, and gear that is switched off. If nothing is at risk in it, it does not need watching yet, but note it, because the day you start using it, it goes on the list.
Match the sensor to the unit
A coolroom you walk into and a bar fridge at the pass are different jobs. A freezer at minus 18°C needs a sensor rated for it, which is its own topic in freezer temperature monitoring for a food business, and a prep fridge with a lid that opens all shift needs sensible alerting so normal door-opens do not cry wolf. Same rule, though: one per box.
The short version
Count independently-refrigerated units, not rooms. Every fridge, freezer and coolroom fails on its own, so each one gets its own sensor. Walk the fit-out, count every box that makes its own cold and holds stock, and put a sensor on each. One sensor "for the kitchen" covers one unit and leaves the rest blind, and it is never the covered one that dies.
General guidance for planning coverage. Your final count depends on your actual fit-out and how each unit is refrigerated.
Want a hand counting your units and working out what goes where? Send through what is in your kitchen and we will map one sensor per box. Tell us what you need to watch and we will point you straight.