Refrigerated Warehousing & Cold Stores: Cold storage installers

A refrigerated warehouse, or cold store, is cold storage at industrial scale: a large insulated building holding hundreds to tens of thousands of pallets of chilled or frozen product, served by central refrigeration plant. It is the most capital-intensive and the most energy-intensive cold storage type, and it is where the economics of the cold chain are decided. Refrigeration is 70 to 80 per cent of the electricity bill on one of these sites, and that bill runs into the hundreds of thousands of pounds a year on a large frozen store, so the plant, the envelope and the operating discipline matter more than the sticker price. This page covers what a refrigerated warehouse is, how it is sized in pallet spaces and refrigeration duty, how it is designed and built, what it costs to install and run, and the redundancy and compliance decisions that protect the stock and the audit.

What a refrigerated warehouse is, and who needs one

A refrigerated warehouse holds product at a controlled temperature at pallet scale: chilled at 0 to +5°C, frozen at -18 to -25°C, or a combination across separate chambers. It is built from a large-span insulated envelope over racking, with central or distributed refrigeration plant, dock doors for goods in and out, and the controls, monitoring and alarms needed to run it as a food-grade facility around the clock.

The buyers are the backbone of the cold chain. Third-party logistics (3PL) operators and food-service distributors run cold stores as their core business. Supermarket regional distribution centres hold chilled and frozen stock for store replenishment. Frozen and chilled manufacturers keep finished product on site, and seafood and meat wholesalers hold stock between landing or slaughter and sale. The decision is a board-level capital project: an operations or engineering director specifies it, a finance director signs the capex, and both care intensely about running cost, resilience and passing customer audits, because a cold store that fails an audit or loses a store of stock threatens the contracts the business runs on.

How a refrigerated warehouse is sized

At this scale, sizing works on two axes at once: storage capacity in pallet spaces, and refrigeration duty in kilowatts of cooling.

• Pallet spaces. Capacity is counted in pallet positions, from around 500 in a modest store to 30,000 or more in a large distribution centre. Rack layout, aisle type (wide aisle, narrow aisle, drive-in, or automated high-bay) and clear internal height all determine how many pallets fit in a given footprint.
• Refrigeration duty. The plant is sized on the total heat load: product pull-down and holding heat, ingress through the large envelope, air infiltration through dock doors and internal openings, fan and lighting gains, defrost energy, and the effect of goods movement. On a busy store the dock and door infiltration load alone is substantial, which is why air curtains, rapid-action doors and dock seals are specified from the outset.
• Temperature lift and COP. A chilled store runs at a COP of roughly 2.5 to 3.5; a frozen store at roughly 1.5 to 2.2 because the lift is larger. The COP is why a frozen pallet costs materially more to hold than a chilled one, and why plant efficiency dominates the operating cost of a frozen store.
• Half-hourly load data. For an existing operation we pull half-hourly meter data and throughput before fixing the duty, so the plant is matched to the real demand pattern rather than a rule of thumb. Getting this right is the single biggest influence on the lifetime running cost.

We size to N+1 so a single compressor failure cannot lose the stock, and we design the plant to run efficiently at part load, because a large store spends most of its life below peak demand and part-load efficiency is where the money is saved.

How a refrigerated warehouse is designed and built

The insulated envelope

The envelope is a large-span build in PIR or mineral-wool insulated panel, detailed to seal the vapour barrier continuously so warm, moist air cannot track into the insulation and condense. Freezer stores need thicker panel and careful floor design: an insulated, heated or ventilated sub-floor prevents the ground freezing and heaving beneath a slab held below zero. The envelope must meet Building Regulations Part L insulation standards, and on a store of this size a tight, well-detailed envelope is worth a great deal in avoided running cost over its life.

Central plant and refrigerant

Large stores use central pack plant or distributed plant, increasingly built on CO2 (R744) transcritical systems or low-charge ammonia (R717) rather than legacy HFCs. The plant room houses the compressor packs, controls and safety systems; condensers or gas coolers sit outside on a plant deck with free airflow. Floating head-pressure control lets the plant take advantage of cooler ambient conditions to run more efficiently. Pipe runs, plant siting and airflow are engineered to protect efficiency and to meet noise limits at the site boundary.

Doors, docks and infiltration control

Infiltration through openings is one of the largest controllable loads on a busy store, so the goods-in and goods-out design matters. Dock levellers, insulated dock doors, dock seals or shelters, air curtains and rapid-action internal doors all cut the warm, humid air admitted during loading and picking. Strip curtains protect chamber openings on the pick face. These measures are among the cheapest kilowatts a store can save and are specified as part of the build, not bolted on afterwards.

Controls, monitoring and temperature mapping

A food-grade cold store is run on data. Continuous temperature monitoring across every chamber, with alarms and remote alerting, flags a problem before stock is at risk. On commissioning, each chamber is temperature-mapped with calibrated probes to confirm it holds setpoint evenly with no warm spots, and that mapping is the evidence a BRCGS or customer audit expects. We hand over full commissioning records, calibration certificates, F-gas documentation and the PSSR written scheme of examination.

What a refrigerated warehouse costs to install and run

Real UK costs, 2025-26, for a full design-and-build cold store run from £500,000 to £10m or more, driven by pallet capacity, chilled versus frozen duty, rack and automation type, and the plant specification. A modest chilled store sits at the lower end; a large automated frozen distribution centre with high-bay racking and low-charge ammonia plant sits at the top.

Running cost is where a cold store earns or wastes money for its whole life. Refrigeration is typically 70 to 80 per cent of the site electricity bill, and a large frozen store can run into the hundreds of thousands of pounds a year, because a refrigerated facility costs up to four times more per square foot to run than an ambient warehouse. The four levers on that figure are efficient plant, a tight insulated envelope, door and infiltration control, and offsetting the load. Modern CO2 transcritical plant has been shown to cut energy against legacy R404A by around 19 per cent, and low-charge ammonia is more efficient still at the largest scale. Our cold storage cost guide quantifies the capital and running costs, and the grants and funding page covers the tax reliefs that apply to a build of this size.

Payback on the efficiency case is typically around five years, but for a warehouse operator the decisive factors are usually resilience and audit compliance, because those protect the contracts the store exists to serve.

Refrigerant choice and the F-gas phase-down

At warehouse scale the refrigerant decision is strategic. The GB F-gas quota is tightening toward an 80 per cent cut in HFC supply by 2036, and R410A is already excluded from most new equipment, so a legacy HFC store is a long-term liability: the gas gets scarcer and dearer to service, and an early replacement becomes likely. New stores are designed on natural refrigerants that sit outside the phase-down. CO2 (R744) transcritical suits most chilled and frozen duties and is efficient in the UK climate. Low-charge ammonia (R717) is the efficient choice for the largest industrial stores. R290 (propane) suits smaller packaged plant. The government’s gov.uk F-gas guidance sets out the timetable, and choosing a natural refrigerant now protects a store that will be operating well beyond 2036.

N+1 redundancy: protecting the stock

For a store holding significant stock value, N+1 redundancy is not optional. N+1 means installing one more compressor than the load strictly requires, so that if one fails the remaining plant still holds temperature and the stock is protected while the failed unit is repaired. The buyer’s single biggest fear is a plant failure spoiling a full store overnight, and N+1 is the direct engineering answer to it. On a large store we design the whole plant around resilience: N+1 compressors, redundant condensing, dual power feeds where justified, and monitoring that alerts before a drift becomes a loss. We cost redundancy explicitly against the value of the stock and the cost of an outage, so the decision is made on numbers.

Compliance and accreditation

A refrigerated warehouse operates under a stack of regulation:

• GB F-gas Regulation. Leak checking, record-keeping and quota-driven refrigerant management, delivered by an F-gas certified (REFCOM registered) company. The refrigeration engineering standards are the domain of the Institute of Refrigeration.
• PSSR and PUWER. The pressure system needs a written scheme of examination; the plant is work equipment under PUWER.
• BRCGS, SALSA and HACCP. Documented, mapped and alarmed temperature control, traceability and validated storage temperatures. This is what customer and third-party audits examine.
• Building Regulations Part L. Insulation and U-values on the envelope.
• ATP. Where storage links to international temperature-controlled transport.

We build to these standards and commission with the mapping, validation and documentation that make the store audit-ready from handover.

Cutting the running cost with solar

A refrigerated warehouse has the ideal load profile for on-site solar: a large, flat, around-the-clock demand that generation feeds straight into, so self-consumption is very high and export is minimal. A rooftop array on a big cold store offsets a meaningful slice of the largest cost on site, on top of what efficient plant and a tight envelope already save. It is a complement to good refrigeration engineering, not a substitute for it. Sizing that array against the store’s half-hourly load, and modelling the offset, is handled by our sister service specialising in solar for refrigerated warehouses and cold stores.

Frequently asked questions

How many pallet spaces can a cold store hold?

Anywhere from around 500 in a modest store to 30,000 or more in a large distribution centre. The number depends on footprint, clear internal height, and the racking and aisle type: narrow-aisle, drive-in and automated high-bay layouts fit far more pallets into a given footprint than wide-aisle racking.

CO2 transcritical or ammonia for a large store?

Both sit outside the HFC phase-down. CO2 (R744) transcritical suits most chilled and frozen stores and is efficient in the UK climate. Low-charge ammonia (R717) is more efficient still at the largest scale but carries additional safety engineering because ammonia is toxic. We choose based on store size, duty and site constraints, and design the safety systems accordingly.

How long does a cold store build take?

A full design-and-build refrigerated warehouse runs several months from survey through envelope, plant installation, commissioning and validation. We can install alongside a live operation on an extension, interrupting only for tie-in and commissioning, scheduled around your quietest window.

Do I really need N+1 on a warehouse?

For any store holding significant stock value, yes. A single plant failure without redundancy can spoil an entire store overnight, and the cost of that loss, plus the contract risk, far exceeds the cost of the extra compressor. N+1 is standard on stores of this scale for exactly that reason.

Related cold storage services

A warehouse often works alongside faster and smaller cold storage. Add a blast freezer or blast chiller for rapid pull-down before holding, or bring in modular and containerised cold storage for seasonal peaks or as temporary cover during a plant swap. To scope a design-and-build store from your pallet requirement, throughput and half-hourly load, request a quote.