How much electricity does commercial refrigeration waste?
The levers that decide a fridge's running cost — setpoint, doors, defrost, condenser, compressor health — and how to measure them without a meter on every cabinet.
Refrigeration runs 24 hours a day and is routinely one of the largest electricity loads in a food business, a pharmacy or a care home kitchen. Industry guidance for commercial refrigeration — for example the Carbon Trust's refrigeration energy-saving material — has long made the same point: a large share of that consumption is avoidable, and most of the waste comes from a handful of causes. The figures below are approximate and are stated as such.
The levers
Setpoint. Every degree a cabinet is held colder than it needs to be costs roughly 2–4 % more energy, according to commonly cited industry guidance. Cabinets set to 1 °C "to be safe" when 4 °C would keep the food inside its band are the most common finding in a first survey. Tempa uses 2.5 % per degree as a conservative default and labels every saving as an estimate.
Doors. Each opening lets warm, humid air in; the compressor then works to remove both the heat and the moisture. Minutes open per day, and especially long openings during restocking, are visible in a door sensor's record and in the temperature trace that follows.
Defrost. Scheduled defrost cycles are necessary on most cabinets, but a defrost that runs more often or for longer than needed is pure waste. Recognising the periodic spikes in a temperature record lets you count them and exclude them from excursion statistics.
Condenser and seals. A dirty condenser or a worn door seal shows up as a compressor that runs more of the time to hold the same temperature. Tracking the compressor's duty cycle against its own 30-day baseline catches this long before the cabinet fails.
Compressor health. A compressor running more than about 85 % of the time, or starting many times an hour, is undersized, iced, failing or fighting a leak. Either way it is burning electricity and heading for a breakdown.
Measuring without a meter on every cabinet
A clip-on current clamp on each refrigeration circuit, read by a LoRaWAN current converter, gives the current signature of every compressor: on, off, how long, how often. Multiplying by an assumed voltage and power factor gives an energy estimate — good enough to rank cabinets, find overcooling and track drift, as long as the estimate is labelled. Where true kilowatt-hours matter (billing, grant claims) a kWh meter behind a LoRaWAN Modbus bridge gives measured consumption on the circuits that justify it.
A worked example
Twelve cabinets, each assumed to use about 1,200 kWh a year (approximate; real figures vary widely), all held 2 °C colder than needed. At 2–3 % per degree that is 4–6 % of 14,400 kWh, or 576–864 kWh a year — roughly £158–£238 at 27.5 p/kWh. This is a modelled example, not a measured customer result; the point is that the arithmetic is simple once the data exists, and the data is a by-product of the temperature monitoring the business needs anyway.
That is why Tempa shows energy next to temperature on every asset and reports savings against each cabinet's own baseline — and why we think a thermometer is the right place to start an energy company.
The demo dashboard runs on simulated sensors through the same path as real hardware.