Every energy review I have been asked to look at starts in the same place. Lighting. It is visible, the payback is easy to calculate, and somebody can put a number in a board pack by Friday. Meanwhile the refrigeration plant, which is drawing several times more power and running every hour of every day including Christmas, gets a line that says "maintenance ongoing".
I understand why. Refrigeration inefficiency is invisible. A fridge running badly and a fridge running well look identical from the shop floor and both hold temperature, right up until one of them does not. The difference only appears on a bill that never itemises it.
The scale of it
Start with the proportion, because it determines how much attention this deserves. Research from Imperial College London, published in Applied Energy, notes that refrigerators account for around 50% of the total electricity consumed in supermarkets, and that food retail is responsible for roughly 3% of UK electricity consumption.
Hospitality sits lower than that, because kitchens have gas, extract and cooking loads competing for the total. Even so, refrigeration is usually the largest single continuously running electrical load in the building. A fryer draws more when it is on. Refrigeration is always on.
That continuity is the whole point. A ten percent inefficiency on something that runs four hours a day is a rounding error. The same ten percent on something running 8,760 hours a year is a real number, and it compounds quietly across every site in the estate.
Where the losses actually are
In rough order of how much money they waste against how cheap they are to fix.
The condenser
If you fix one thing, fix this. A refrigeration system rejects heat through the condenser. When the fins are coated in dust, grease or fluff, that heat cannot leave, so head pressure rises, so the compressor works harder for the same cooling effect, so it draws more current, every hour, forever.
It also shortens compressor life, which means the energy penalty arrives with a capital penalty behind it. The clean itself is unskilled and cheap. The reason it does not happen is almost always access: a condenser on a roof, behind a grill, or in a plant area needing a permit does not get cleaned. That is a design problem producing an energy cost, and it is worth spending money to fix the access rather than accepting the consequence.
Doors and seals
A worn gasket does not stop a fridge working. It lets warm moist air in continuously, which loads the evaporator, ices the coil, and extends run times. On freezers the effect compounds, because the ice then interferes with defrost and airflow. Seals are cheap, replacing them is quick, and it is one of the most commonly deferred jobs in the industry. Our guide to replacing a door gasket covers how to spot one that has gone.
Refrigerant charge
An undercharged system does not cool as effectively, so it runs longer to hold the same temperature. It also usually means there is a leak, which is a compliance issue and a cost issue at once. Repeated topping up is not maintenance. Our piece on what regassing actually involves explains why a system that has been gassed three times has a problem that gas will not solve.
Defrost strategy
Defrost puts heat deliberately into a system you are paying to keep cold, so it should run only as long as it needs to. Many systems are set to run to time-out on every cycle rather than terminating on temperature, which means the full heat input every time regardless of whether the coil cleared in half the time. Adjusting termination is a controller setting, not a capital project, and on a large estate it adds up.
Night blinds and covers
Open retail cases run against the room all night for no trading benefit. Blinds and covers work, and the failure mode is behavioural rather than technical. If pulling them down is not on the close-down checklist, it will happen at some sites and not others, and the estate-level saving evaporates.
Controls set on installation day and never reviewed
Set points drift into folklore. Somebody once set a cold room to 1°C because a delivery arrived warm, and it has run 3°C colder than it needs to for eleven years. Every degree colder than necessary costs energy for no benefit. Check set points against what the product actually requires, with the legal ceiling in mind rather than as a target.
Ambient conditions
A condensing unit in a hot, unventilated plant room is being asked to reject heat into air that is already warm. Sometimes the highest-value energy intervention on a site is a ventilation grille, not anything on the refrigeration system at all.
The capital-side decisions
The items above are maintenance and behaviour. These cost real money and are worth modelling properly.
| Intervention | What it changes | When it makes sense |
|---|---|---|
| Doors on open cases | Removes the air curtain load entirely | Where merchandising impact is acceptable |
| EC fan motors | Lower fan power, and less heat rejected into the case | Retrofit on older cabinets with shaded-pole motors |
| Variable speed compressors | Matches capacity to load instead of cycling | Systems with widely varying load |
| Floating head pressure control | Lets head pressure drop when ambient allows | Systems with fixed high head pressure set points |
| LED case lighting | Less power, and less heat inside the case | Almost always, on older cases |
| Heat recovery | Uses rejected heat for hot water or space heating | Larger systems with a matching heat demand |
| Full system replacement | Everything, including refrigerant exposure | When reactive spend and efficiency losses both justify it |
A note on the last row. Replacement decisions in refrigeration should be modelled on three things together: current reactive spend, energy penalty against a modern equivalent, and refrigerant exposure. Most estates model only the first, which is why replacements get deferred past the point where they made obvious sense. Our guide to judging repair against replacement covers how to structure that.
The refrigerant dimension
Energy and refrigerant policy are more connected than they look. Higher-GWP refrigerants push systems into more frequent leak check bands and are subject to the quota phase-down, which drives price and availability. A system that is expensive to run and holds a refrigerant that is getting harder to buy is a replacement candidate on two independent grounds.
Systems using CO₂ as a refrigerant avoid the quota issue entirely, and their efficiency in UK ambient conditions is generally good, though they are not automatically right for every application. Our piece on the R410A phase-out covers how that pressure has played out on price so far.
Measuring it, so you know rather than guess
Most of the above are known good practice. What separates estates that actually save money is measurement, because it tells you which of your sites has the problem.
- Sub-meter refrigeration where you can. A single site meter tells you nothing about which system is the problem.
- Compare like sites. If twelve stores have identical kit and one uses noticeably more, that is a fault, not a fluctuation. This only works if the estate is standardised, which is one of the underrated arguments for standardising it.
- Record readings on every planned visit. Suction and discharge pressures, superheat, subcooling, current draw. A service report with numbers gives you a trend. A report that says "system OK" gives you nothing.
- Watch run time, not just temperature. A system holding temperature while running 95% of the time is failing slowly. Temperature alone will not show you that.
- Trend the current draw on compressors. Rising amps at a constant load is an early warning that costs nothing to spot and a lot to ignore.
That fourth point is the one I would push hardest. Run time is the most useful refrigeration metric that almost nobody records, and it is available from most modern controllers for free.
A sensible order to do this in
- Clean every condenser and fix the access problems that stopped you.
- Replace worn door seals across the estate in one programme rather than one at a time.
- Review set points and defrost termination on every system.
- Leak test properly, repair rather than top up.
- Put night blinds and covers into site routines, not just into the building.
- Start recording run time and current draw at every planned visit.
- Then, with data, model the capital interventions on the sites that justify them.
Steps one to five cost very little and are mostly a matter of doing what should already be happening. Step six costs nothing at all. Only after that does it make sense to spend capital, because by then you know where.
The connection to maintenance
Almost everything on that list happens during a properly scoped planned visit. That is the argument for a maintenance regime that most people miss: the case is usually made on avoided breakdowns, and the recurring energy saving from equipment kept at design efficiency is frequently the larger number, it just never appears on an invoice.
A planned visit that cleans the condenser, checks the charge, verifies defrost and records the readings is doing energy work whether or not anyone calls it that. A twenty-minute visit that produces a signature is not, and it costs the same. Our guide to setting service frequencies by asset covers what a visit should actually contain, and what a maintenance contract really covers deals with getting that written into the agreement.
If you want a view on where your estate is losing energy, we are happy to survey a sample of sites and report what we find, including the readings. You can see how we structure planned refrigeration servicing, read about running costs on the air conditioning side, or get a quote.
About the author: Ali Elm runs Be Cool Refrigeration & Air Conditioning, a family-run London firm that has been installing, servicing and repairing commercial refrigeration and air conditioning since 2004. His F-Gas certified team has delivered more than 2,000 projects across London and the South East.
Written by
Ali Elm
Ali is the Head of Operations at Be Cool Refrigeration with over a decade of hands-on experience in HVAC and commercial refrigeration. He oversees every installation, repair, and maintenance project, making sure the work meets the highest standards. Ali holds full F-Gas certification and has worked across residential, commercial, and industrial refrigeration systems throughout London and the South East. When he is not on site, he writes these guides to help business owners and homeowners understand their cooling systems better.