Big-box logistics: EPC assessment for new-build and refurbished sheds

Why big-box logistics is its own assessment problem

A distribution shed is not simply a larger industrial unit. It is a building type with an unusual energy signature: an enormous conditioned or semi-conditioned volume, a very low ratio of fixed services to floor area across the storage envelope, and then dense, highly serviced pockets - the office pod, the welfare block, the transport office, and increasingly chilled or temperature-controlled zones.

That combination produces results that surprise developers in both directions. A plain, sparsely serviced shell can rate well precisely because there is so little fixed plant relative to its footprint. Add a two-storey office pod, comfort cooling and a chilled area, and the same building moves into a materially different assessment - more zones, more systems, and a rating driven by a small proportion of the floor area.

This page is about developing and refurbishing that space so it rates well. If you have an existing industrial unit or warehouse and simply need it certified, our industrial units and warehouses EPC page is the more direct route.

New build: the EPC is required on construction

A new commercial building requires an EPC on construction. That is a separate trigger from sale or letting, and it applies whether or not an occupier has been found - which matters on speculative development, where the building is completed and certified long before a tenant is in place.

All new-build commercial work is assessed at SBEM Level 4 as a minimum, regardless of how simple the building looks. Where the design includes features SBEM cannot model reliably - atria, automated blind control, or advanced HVAC control strategies - the building requires Dynamic Simulation Modelling at Level 5 using specialist software.

The practical consequence is that the assessment belongs in the design programme, not at practical completion. Modelling the building while the specification is still movable lets you see what a change to lighting control, heating strategy or the office-pod servicing does to the rating while it still costs a specification decision rather than a remedial works package.

What it takes to rate EPC A or B on a shed

The queries we see most often on this subject are about achieving an A or A-plus rating on a distribution building, usually because an occupier or an investor has asked for it. It is achievable, and on a new build it is far more achievable than on a retrofit, but the levers are not evenly weighted.

The largest gains generally come from the fixed services rather than from insulating the envelope further. Lighting is the single biggest one across a large floor plate: LED throughout with genuinely effective controls - zoning, daylight linking and presence detection across a space that is mostly unoccupied most of the time. Heating strategy is next, particularly the choice between destratified warm air, radiant systems and heat pumps, and the control granularity applied to the office and welfare pockets that actually need conditioning.

On-site generation matters too. Where an EPC recommends on-site generation, the roof area on a big-box building is exceptional relative to its energy demand, and the effect on the rating can be substantial. That is a design-stage decision about roof loading and plant space as much as an energy one.

One caution worth stating plainly: the rating reflects the building fabric and its fixed services under standardised assumptions. It does not reflect the racking, the conveyors, the automation or the fleet. A highly automated facility can hold an excellent certificate while consuming a great deal of electricity, and a lightly used shed can rate poorly. Do not let an occupier read the certificate as an operating-cost forecast, because it is not one.

Fit-out and subdivision: the trigger developers miss

Big-box space frequently completes as a shell and is fitted out for an incoming occupier afterwards. That fit-out is the trigger most often missed, because it does not feel like construction to the people managing it.

Work that changes the building fixed services - installing or replacing heating, cooling, ventilation or lighting, or subdividing a single shell into separately serviced units - can amount to a qualifying refurbishment requiring an EPC in its own right. Subdivision also changes the assessed extent: a certificate covering the whole shell no longer describes the units being let individually, even if it has years left to run.

On a multi-let scheme the practical rule is that each separately let unit needs a valid certificate covering that unit and its own fixed services. Establishing this before the fit-out is specified is straightforward; reconstructing the evidence afterwards is not.

MEES and the investment case

For a developer or investor the compliance floor is EPC E: since 1 April 2023 it has been unlawful to CONTINUE letting a non-domestic property below E, not merely to grant a new lease. New-build logistics will comfortably clear that floor, so on new stock MEES is rarely the binding constraint.

The forward-looking constraint is the proposed standard: privately rented non-domestic buildings over 1,000 sqm reaching EPC B by 2031, subject to secondary legislation. Essentially every big-box building is over that threshold, so this is the cohort the proposal is aimed at. Two widely repeated dates are wrong and should not appear in an appraisal: in the government response of 18 June 2026, the interim EPC C milestone for 2027 was dropped, and "EPC B by 2030" was never the proposal.

The sensible reading for a development appraisal is that a building specified to a B or better today is insulated against the proposal as it currently stands, while a building specified to scrape a C carries a re-fit risk on a timescale nobody can yet price precisely. That is a specification decision made once, at design stage, for a fraction of what the same improvement costs later around a sitting tenant.

Cold storage and temperature-controlled space

Temperature-controlled and chilled space inside a distribution building deserves separate thought, because it is the area where owners most often misjudge what the assessment covers. Fixed cooling plant that forms part of the building services sits inside the calculation. The goods being stored, and process refrigeration that is genuinely equipment rather than building services, do not.

That line is finer in a cold-storage building than almost anywhere else, and where it falls materially changes both the assessment level and the result. If a scheme includes chilled or frozen space, it is worth having that boundary established explicitly at design stage rather than discovering at completion that the modelling assumed something different from what was built.

Refurbishment and repositioning of older sheds

A great deal of the logistics stock now being traded is not new. Sheds built in the 1990s and 2000s are being repositioned - re-clad, re-roofed, re-lit and re-serviced - for occupiers who expect a rating the original building was never designed to reach.

Refurbishment of this kind is usually a qualifying refurbishment in its own right, so the certificate is required regardless of whether the building is being sold or let afterwards. It is also the point at which the biggest rating gains are available for the least marginal cost, because the lighting and the heating are coming out anyway. Specifying the replacement to a rating target rather than to a like-for-like standard is typically a small increment on work already committed.

The envelope is the harder part. Re-cladding and re-roofing give a genuine fabric improvement, but on a building of this volume the payback is driven more by the services and the controls. Where budget is finite, the modelling will usually show that lighting, controls and heating strategy buy more rating per pound than further insulation.

What we need to model it properly

For a new build or a major refurbishment the modelling is only as good as the information behind it. The useful set is the architectural drawings with areas and construction build-ups, the M&E specification covering heating, cooling, ventilation and lighting with control strategies, glazing and rooflight specifications and areas, air-permeability design targets and test results, and details of any on-site generation.

Where that package exists, the assessment is efficient and the result is defensible. Where it does not, the assessor has to measure and make conservative assumptions, and conservative assumptions cost rating points. On a building of this scale that is the difference between a specification that achieves its target band and one that misses it on paper despite being built correctly.