Domestic EPC vs Commercial EPC Explained

A flat above a shop, a converted office, a house in multiple occupation and a warehouse can all create uncertainty over which certificate is needed. The difference between a domestic EPC vs commercial EPC is not simply the size of the building. It depends on how the space is constructed, used and legally defined, which affects the assessment method, the information required and your compliance responsibilities.

For landlords, sellers and property managers, arranging the wrong assessment can mean delays to a sale, letting or marketing launch. Establishing the correct EPC type early keeps the process straightforward and helps ensure the certificate reflects the property accurately.

Domestic EPC vs commercial EPC: the main difference

A domestic Energy Performance Certificate applies to a dwelling - a self-contained home intended for residential use. This includes houses, flats, maisonettes and many holiday homes. A domestic EPC gives the property an energy rating from A to G and includes recommendations that may improve its efficiency.

A commercial EPC, formally known as a non-domestic EPC, applies to buildings used for business or public-facing activity. Typical examples include offices, shops, restaurants, industrial units, warehouses, surgeries and schools. It also uses an A to G scale, but the calculation method is different because commercial buildings have more varied heating, cooling, lighting and ventilation systems.

The practical point is simple: a certificate is tied to the building or unit being sold, let or constructed. A residential flat within a mixed-use building may need a domestic EPC, while the ground-floor retail unit needs a commercial EPC. One certificate will not usually cover both independently occupied spaces.

How each EPC is assessed

Domestic EPCs are generally produced using Reduced Data Standard Assessment Procedure, often called RdSAP. During the visit, an accredited domestic energy assessor records visible features such as insulation, windows, heating systems, hot water provision, lighting and renewable technologies. The assessment is based on the dwelling as it stands on the day.

This is why access to the loft, boiler, electric meters and all rooms is useful. Supporting evidence can also make a difference. For example, documentary proof of wall insulation or a new boiler specification may allow the assessor to record an improvement that cannot be confirmed through a visual inspection alone.

Commercial EPCs are typically calculated using Simplified Building Energy Model, known as SBEM, or another approved non-domestic methodology. The assessor needs to understand the building’s layout, construction, use, occupancy zones and services. Lighting design, air conditioning, mechanical ventilation, heating controls and glazed areas may all have a material effect on the rating.

A commercial survey can therefore require more preparation than a domestic visit, particularly where a site is large, has several occupiers or contains specialist systems. Accurate floor plans, building information and details of recent works can help avoid assumptions and reduce follow-up queries.

Why a commercial EPC is not just a larger domestic EPC

Domestic assessments are designed around homes, where energy use is largely influenced by fabric, heating and hot water. Commercial assessments must account for the fact that an office with extensive lighting and cooling operates very differently from a warehouse with limited heating, even if their floor areas are similar.

This also means a commercial rating may be affected by how a unit is configured and used. A vacant shell, fitted restaurant and open-plan office can each require a different approach. Getting the building use right is essential to a reliable result.

When you need an EPC

In most cases, an EPC is required when a property is built, sold or let. Sellers and landlords should have the certificate available when marketing begins, rather than waiting until a buyer or prospective tenant asks for it. Estate agents and letting agents also need the rating for property listings.

For a domestic rental property in England and Wales, the minimum energy efficiency standard is normally an E rating, unless a valid exemption applies. The same broad E threshold applies to many non-domestic rented properties. However, the exemptions, improvement options and evidence requirements can be more complicated for commercial premises, especially where tenant alterations, listed status or cost-related issues are involved.

A certificate is usually valid for ten years, provided no newer EPC has been produced for the same property. Validity does not remove the need to consider current Minimum Energy Efficiency Standards when letting a property. A ten-year-old certificate may still be valid, but it may show a rating that prevents a new tenancy or lease from proceeding without improvements or an exemption.

Scotland has separate regulations and processes in some areas. If a property is located there, it is sensible to check the applicable Scottish requirements before arranging an assessment.

Mixed-use buildings and common problem areas

Mixed-use properties are where most confusion arises. A building with a shop below and a flat above will often need two EPCs if the spaces are separately accessed or capable of separate occupation. The shop requires a commercial EPC and the flat requires a domestic EPC.

The position can be less clear where there are shared services, internal connections or areas that serve more than one occupier. A landlord may own a building as a single investment, but that does not automatically mean it receives one certificate. The assessment must reflect the individual unit or building being marketed or let.

Other cases that need careful consideration include HMOs, holiday lets, care homes, live-work units, converted barns and buildings with residential accommodation attached to a business. The intended use and degree of self-containment matter more than the label used in an advert or tenancy agreement.

If you are unsure, provide as much information as possible when requesting a quote: the address, property type, floor plans if available, current use, whether there are separate entrances and whether the unit is being sold or let independently. This allows the assessor to advise on the appropriate route before the visit is booked.

Cost, survey time and what affects the price

Domestic EPCs are usually quicker to complete and are commonly priced on the size and complexity of the home. A standard house or flat can often be surveyed efficiently where access is straightforward and the necessary areas are available.

Commercial EPC prices vary more widely. A small retail unit may be relatively simple, while a multi-storey office, restaurant or industrial building with complex services needs a more detailed survey and modelling process. Floor area, number of zones, building systems, location, access arrangements and the availability of plans all influence the cost and turnaround time.

Choosing the lowest quote without checking the service can be a false economy. For either assessment type, use an accredited assessor who is insured and able to explain what is needed before the appointment. Clear communication is particularly valuable where a transaction has a fixed completion date or a tenancy renewal depends on an acceptable rating.

Preparing for your EPC assessment

Good preparation helps the assessor work efficiently and gives the property the best chance of being represented correctly. For a home, make sure the boiler, hot water cylinder, loft hatch and electric meters are accessible. Keep paperwork for insulation, replacement glazing, solar panels or heating upgrades available where possible.

For commercial premises, prepare current floor plans, details of HVAC equipment, lighting upgrades and any renewable installations. Arrange access to plant rooms, roof-level equipment and all parts of the unit. If another party manages the building services, such as a freeholder or facilities manager, obtain the relevant information before the survey.

Do not assume that an improvement is automatically reflected in the EPC. The assessor needs suitable evidence and must follow the approved methodology. If evidence is unavailable, they may have to record the feature using the default assumptions set by the system.

EPCs, recommendations and improvement planning

An EPC is a compliance document, but it can also help inform investment decisions. The recommendations section identifies measures that may improve energy performance, such as insulation, heating controls, low-energy lighting or upgrades to heating and cooling equipment.

For landlords, these recommendations can support a practical plan to protect lettability and reduce the risk of future compliance issues. For homeowners, they can provide a useful starting point before remortgaging, selling or planning wider renovation work. Commercial owners may need more detailed advice before committing to major changes, particularly where works affect lease obligations, planning or building control.

A certificate should not be treated as a full retrofit design. Where substantial improvements are planned, a retrofit assessment or specialist energy advice can provide a clearer picture of the order of works, likely interactions between measures and the condition of the building.

The right EPC starts with a clear understanding of the property you are dealing with. Whether you are marketing a flat, renewing a shop lease or managing a mixed-use building, arranging the correct assessment early gives you time to deal with the rating, paperwork and any improvement decisions without last-minute pressure.