epcforbusinesses.co.uk
Get a Quote

Level 5 EPC cost: what drives the price of a DSM assessment

Updated 19 October 2026 · SEO Dons Editorial

When does a building need a Level 5 EPC?

Government guidance defines level five buildings as those for which the dynamic simulation model (DSM) is used to carry out the assessment. DSM is used where the standard Simplified Building Energy Model (SBEM) may not be sophisticated enough to give an accurate assessment of a building's energy efficiency.

In practice that means unusual design features. Elmhurst Energy, one of the approved accreditation schemes, lists atria, automatic shading systems, extensive use of thermal mass and highly glazed facades as typical Level 5 features. The non-domestic EPC conventions go further on one of them: every atrium is treated as a Level 5 feature.

The building sets the level, not the owner. If you are not sure whether yours is Level 3, 4 or 5, the side-by-side comparison is in the guide to SBEM Level 3 and 4 versus DSM.

Why does a Level 5 EPC cost more than SBEM?

Three things change when a building moves up to Level 5: the method, the assessor and the amount of data that has to go in.

  • The method. The government guide describes DSM as a software tool that models energy inputs and outputs for a building over time. It is a full simulation rather than SBEM's simplified calculation, and only government-approved software can be used to produce the certificate.
  • The assessor. An EPC must be issued by an energy assessor accredited for the category of building it relates to, and a scheme's approval can be limited by building category. Elmhurst says Level 5 assessors are specifically trained and approved to use DSM software, so the job needs someone with that extra accreditation rather than any non-domestic assessor.
  • The inputs. CIBSE's Energy Performance Group describes DSM packages as using the actual building geometry, details of construction materials, HVAC design strategies, solar gain, occupancy data and hourly weather data. Each of those has to be gathered, checked and entered.

The government guide says the price of an EPC is set by the market and is likely to vary with the size, location and age of the building, and GOV.UK says the cost depends on the building being assessed. For the price factors that apply at every level, see the commercial EPC cost guide.

How much does modelling time add?

A DSM model is built from the building's real geometry. Before any calculation runs, the assessor has to recreate the shape of the building, its zones, its glazing and its orientation in the software. CIBSE's note on DSM says how quickly that can be done depends on the scale and complexity of the building and the accuracy required.

As a hypothetical example, a compact two-storey office with one central atrium is a smaller modelling job than a multi-wing building with several atria, facades facing in different directions and a mix of uses on each floor. Both are Level 5. The second simply has far more surfaces, zones and interactions to set up and check.

Checking takes time too. For level four and five buildings, the government guide says the assessor must visit and inspect every building they certify so they can verify any data provided, and must record the provenance of all the data used to produce the EPC. If assistants help gather data, the assessor has to supervise them and be able to show they are suitably qualified. That supervision and record-keeping is part of what you are paying for.

Which building features push the price up?

The features that put a building into Level 5 are usually the same ones that make it slow to model. The accreditation schemes and the conventions point to:

  • atria, which the conventions treat as a Level 5 feature in every case
  • automatic shading or automatic blind control
  • extensive use of thermal mass
  • highly glazed facades
  • complex ventilation
  • light pipes that pass through a complete storey to serve the floor below, which the conventions say SBEM will not model, pointing to DSM instead

Elmhurst explains that, because of the complexity and interaction of the fabric and services, these buildings cannot be modelled reliably using simplified methods. In cost terms, more interacting features means more zones, more surfaces and more control logic to set up. Elmhurst gives airports and large shopping centres as typical Level 5 examples.

Floor area still matters, but it is not what makes a building Level 5. A modest building with an atrium falls into Level 5, while Elmhurst places larger offices, retail outlets and warehouses with mechanical ventilation or air conditioning at Level 4. The same goes for large hotels: features such as an atrium, not the number of bedrooms, decide whether one needs a Level 5 assessment.

What data does a Level 5 assessor need?

The government guide lists the information needed for any commercial EPC: the zones of the building and their dimensions, the activities in each zone, the heating and ventilation services for each zone (including the type of system, metering, controls and fuel), the lighting and its controls, and the construction of the roof, floors, walls and glazing. A Level 5 model needs all of that, usually in more detail.

Good documents save time. The guide says up-to-date information and plans make the process less time-consuming, although the assessor must still validate the information with a site inspection. For newer buildings, the conventions only accept the design team's documents as evidence if they are "as built". Design-stage documents on their own are not acceptable.

Missing data costs in two ways. It takes longer to survey and measure what is not on paper, and where details cannot be found the assessor may have to fall back on defaults. The conventions say defaults should be avoided where possible, and that an assessor who cannot confirm the details of a heating or cooling generator should work on a worst-case basis. That can push the rating down as well as the fee up.

How does HVAC detail affect the fee?

Heating, ventilation and air conditioning already decide the step from Level 3 to Level 4: government guidance says HVAC is currently the only distinction between those two levels. It treats linked boilers totalling more than 100kW, multi-split and VRF cooling, and central air conditioning (air handling units, all-air, air/water systems and chillers) as Level 4 systems. A Level 5 building can have any of these, combined with features such as automatic blind control or complex ventilation.

For each system, the assessor has to confirm what is installed and how it performs. The conventions give examples of the details an assessor may confirm with the design team, including lighting design, specific fan powers, BMS details and district heating carbon emissions. The more plant there is, and the harder it is to reach, the longer this takes. The conventions also expect assessors to make every effort to gain access to heating and cooling generators, so plant rooms and roof plant need to be reachable on the day of the visit.

How do you get a reliable Level 5 price?

Because the cost follows the building, a useful quote request describes the building rather than just giving a floor area. Before asking for prices, it helps to have:

  • the address and approximate floor area
  • what the building is used for, floor by floor
  • as-built drawings, if they exist
  • a short description of the HVAC, lighting and controls, or the operation and maintenance manuals
  • any features likely to need DSM, such as an atrium or automatic shading
  • the date you need the certificate by, and whether an EPC already exists

Ask each assessor to confirm they are accredited at Level 5, since the certificate must be issued by someone accredited for that category of building. The full checklist is in what you need to get a commercial EPC quote, and the cost page explains how fees are built up across all levels.

Sources

Common questions

Is there an official price for a Level 5 EPC?

No. The government guide says the price of an EPC is set by the market and is likely to vary with the size, location and age of the building. GOV.UK says only that the cost depends on the building being assessed, so a Level 5 figure has to come from a quote.

Will a DSM assessment give my building a better rating?

Not necessarily. DSM is used because SBEM may not be sophisticated enough to give an accurate assessment of some buildings, not because it favours a particular result. The rating depends on the building and on the evidence behind each input.

Can a Level 4 assessor produce the EPC if the building has an atrium?

No. The non-domestic EPC conventions treat all atria as a Level 5 feature, and an EPC must be issued by an assessor accredited for the category of building it relates to. Elmhurst describes a Level 4 qualification as covering buildings classed as Level 4 and below.

Who pays for a Level 5 EPC on a newly built building?

When a new building is complete, the person carrying out the construction has to give the EPC and recommendation report to the building owner. How that cost is shared is a matter for the contract between the parties.

Does a Level 5 EPC last longer than an SBEM one?

No. GOV.UK says all EPCs are valid for 10 years, whichever method produced them. If a newer EPC is lodged for the same building, the older one stops being valid.

Get a commercial EPC quote

By submitting you agree to our privacy policy. We never sell your details.

Get a quote
Get a quote