Commercial EPC vs Domestic EPC: What's the Difference?

A commercial (non-domestic) EPC is assessed with SBEM or DSM software by an accredited Non-Domestic Energy Assessor, while a domestic EPC uses RdSAP and a Domestic Energy Assessor. The rating scale from A to G looks identical, but the method, the assessor qualification, the register the certificate is lodged on and the minimum-standard rules behind it are all different. Booking the wrong one, or assessing the wrong part of a building, is one of the most common and expensive mistakes owners make.

If you have only ever dealt with a home EPC, it is natural to assume a commercial one is the same document for a bigger building. It is not. The two sit under related regulations but run on separate tracks, and treating a shop like a house produces a certificate that is invalid at the exact moment you need it, in a sale or a letting. This guide sets out precisely what changes.

The rating scale is the same. Almost nothing else is

Both certificates present a coloured A-to-G energy rating, so at a glance they look interchangeable. Underneath, they are produced by different people, using different software, following different rules, and stored in different places.

Feature	Domestic EPC	Commercial (non-domestic) EPC
Buildings covered	Houses, flats, dwellings	Offices, shops, warehouses, pubs, care homes, mixed-use commercial floors
Calculation method	RdSAP (Reduced Data SAP)	SBEM (Level 3 or Level 4) or DSM (Level 5)
Assessor	Domestic Energy Assessor (DEA)	Non-Domestic Energy Assessor (NDEA)
Register	Domestic EPC register	National non-domestic EPC register
Minimum standard to let	On a separate domestic MEES track	EPC E now; proposed EPC B by 2031 for over-1,000 sqm privately let buildings
Validity	10 years	10 years
Typical cost basis	Broadly standardised per property	Priced on the building: floor area, systems, zones, assessment level

The shared feature worth remembering is validity: both last ten years from the date of lodgement. Everything above that line, though, means you cannot simply reuse a domestic assessor or a domestic quote for a commercial building.

Different software, different assessor

A domestic EPC is produced using RdSAP, a reduced-data version of the government’s Standard Assessment Procedure built around the way homes are heated and used. A Domestic Energy Assessor gathers a defined set of inputs and the software returns a rating.

A commercial EPC is different in kind, not just in scale. Most non-domestic buildings are modelled with the Simplified Building Energy Model, or SBEM. Simple, smaller premises with straightforward services, a single office suite or a corner shop, are typically assessed at Level 3. Larger buildings, or any with more involved heating, cooling, ventilation and controls, and all new-build commercial regardless of size, move to Level 4. The most complex buildings, those with atria or advanced HVAC that SBEM cannot model reliably, need Dynamic Simulation Modelling, which is a Level 5 assessment. One point worth stating plainly, because it is a frequent error: DSM is Level 5, not Level 4. A Level 4 assessment is still SBEM.

Crucially, a legally valid non-domestic EPC can only be produced by an accredited Non-Domestic Energy Assessor, a member of a government-approved scheme such as Elmhurst, Stroma/NAPIT, Quidos or ECMK, and qualified to the level your building requires. A domestic assessor cannot lawfully lodge a commercial certificate, and vice versa. You can check any existing certificate, and the register it belongs to, using the government’s find an energy certificate service{rel=“noopener”}.

The minimum-standard rules are on separate tracks

This is where the difference stops being technical and starts costing money. Both domestic and commercial property are subject to a Minimum Energy Efficiency Standard, but the two regimes have their own deadlines and their own detail.

For commercial (non-domestic) property, the current minimum to let is EPC E. Since 1 April 2023 it has been unlawful not merely to grant a new sub-E lease but to continue letting a sub-E building, so an old, poor certificate on a currently-tenanted property is a live liability, not a dormant one. The rules are also tightening on the commercial side specifically: on 18 June 2026 the government confirmed that, subject to secondary legislation, privately rented non-domestic buildings over 1,000 square metres are proposed to reach EPC B by 2031, and it dropped the previously floated interim EPC C milestone for 2027. You can read the government interim response on EPC B by 2031{rel=“noopener”} in full.

The domestic MEES timeline is separate and should not be read across. If you have heard a deadline quoted for rented homes, it does not automatically apply to your shop, office or warehouse. When in doubt, work to the rule that governs the specific building in front of you, which is exactly what our commercial MEES FAQs set out.

Where it bites hardest: mixed-use buildings

The single most common real-world trap is the mixed-use building, the shop-with-flats-above found on every UK high street. Here both regimes apply to one address at once.

The rule is straightforward once stated: the commercial floor needs a non-domestic EPC, and each flat needs its own domestic EPC. One RdSAP certificate for the whole building is wrong. One SBEM certificate for the whole building is also wrong. Getting this split right, which parts need a commercial EPC and which need a domestic one, is where mixed-use owners most often end up with invalid or missing certificates and a stalled transaction. If your building has both, plan for both from the outset. Our mixed-use EPC guidance walks through how the two certificates sit together.

Cost works differently too

A domestic EPC is broadly a standardised job. A commercial EPC is priced on the building, because the work genuinely varies: a Level 3 corner shop is a modest survey, while a multi-zone warehouse or hotel at Level 4, or a complex building needing a Level 5 DSM model, involves surveying and modelling every heating and cooling system and every zone. The fee is driven by floor area, the number of building services, the assessment level and site access, not a single headline figure. We break the ranges down in our commercial EPC cost guide.

Common questions

Can a domestic energy assessor do my commercial EPC?

No. A commercial EPC must be produced by an accredited Non-Domestic Energy Assessor qualified to the level your building needs. A Domestic Energy Assessor is accredited for RdSAP home assessments only, and a certificate lodged on the wrong register, or by an assessor not accredited for that building type, is not valid, which defeats the point at completion.

I already have a domestic EPC for my shop-with-flat. Am I covered for the shop?

No. A domestic EPC covers a dwelling. The commercial floor of a mixed-use building needs its own non-domestic EPC assessed under SBEM or DSM. If you were sold a single domestic certificate for the whole building, the commercial part is effectively uncertificated, and a buyer’s or tenant’s solicitor will flag it.

Get the right assessment for your building

If you are selling, letting or refurbishing commercial premises, the safe move is to have the building assessed by an accredited Non-Domestic Energy Assessor to the correct level, and, for mixed-use, to certificate the commercial floor and the flats separately. To get a firm price and turnaround for your specific building, request a free commercial EPC quote and we will confirm the right assessment route before any survey.