Level 5 EPC & DSM Assessments

A More Accurate Model, Often a Better Rating

Most commercial EPCs are produced with SBEM, the Simplified Building Energy Model. The clue is in the name. SBEM works on monthly averages and applies conservative default assumptions wherever specific information about the building is missing. It is a reasonable approximation, and for straightforward buildings it is perfectly adequate.

Dynamic Simulation Modelling works differently. It builds a full thermal model of the building and simulates its behaviour across the whole year, accounting for how the fabric, the services and the occupants actually interact. Thermal mass, solar gains through glazing, shading, daylight-linked lighting control, mixed-mode ventilation: SBEM either ignores these or handles them crudely. DSM models them properly.

The practical consequence is that buildings which genuinely perform better than SBEM's defaults assume tend to score better under DSM. Nothing about the building changes. The assessment simply stops penalising it for information SBEM was never able to take into account.

To be clear about this: a DSM assessment is not a guaranteed uplift and it is not a way of engineering a rating. It is a more accurate calculation, and a more accurate calculation usually rewards a decent building. Occasionally it confirms the SBEM figure, and occasionally it comes out lower. We will look at your building first and tell you honestly whether we think it is worth doing.

Using DSM for MEES Compliance

Since April 2023 it has been unlawful to continue letting a commercial property rated F or G, including on tenancies that were already in place. If your building has fallen the wrong side of that line, the instinctive response is to start pricing up improvement works.

Before you do, it is worth establishing whether the rating is actually correct. A DSM assessment produces a standard, fully lodgeable EPC that counts for MEES in exactly the same way as an SBEM one. If the SBEM figure was dragged down by default assumptions rather than by genuine inefficiency, a Level 5 assessment can establish a compliant rating far more cheaply and far more quickly than physical works.

That is not always the answer. Some buildings are genuinely inefficient and need real improvements. But re-assessing properly first means you find out which situation you are in before spending money on plant and fabric.

The 2031 EPC B target

In June 2026 the government published its response to the long-running MEES consultations. The headline outcome is that commercial buildings above 1,000 square metres will need to reach EPC B by 2031, subject to exemptions and to the necessary secondary legislation being passed. Buildings below that threshold stay at the current E minimum.

Note that the previously proposed interim milestone of EPC C by 2027 has been dropped. Plenty of guidance online still repeats that 2027 date, so it is worth checking any advice you have been given against the current position.

The buildings caught by the 2031 target are the larger ones, and larger buildings are disproportionately the complex ones where DSM makes the biggest difference. If you hold anything over 1,000 square metres, understanding its accurate rating now gives you five years to plan rather than react.

Read our full MEES guide for commercial landlords →

Who This Is For

Landlords with an F or G rated building. You cannot let it, and works are expensive. Establish the accurate rating first.

Owners of anything over 1,000 square metres. The 2031 EPC B target applies to you. Knowing where you genuinely stand is the starting point for any sensible plan.

Anyone whose building has unusual features. If your property has significant glazing, thermal mass, shading or advanced controls, SBEM may well be underselling it.

Portfolio holders. If several buildings sit just below a threshold, a DSM re-assessment across the portfolio is usually cheaper than a works programme.

Complex buildings that legally require it. Atria, automatic blinds, mixed-mode ventilation. For these, Level 5 is the only valid route.

Level 5 work is different from a standard commercial EPC. The modelling is the bulk of the job, and it is done from the drawings, specifications and survey data rather than on site. That means geography matters far less than it does for a routine SBEM assessment, and we are instructed on DSM work well beyond our local patch.

We will still survey the building properly. For a single site anywhere in England, Scotland or Wales that is simply part of the job and it is priced into the quote. For portfolios we will usually plan the visits together to keep the cost down.

If you are a managing agent, building consultant or property manager with a complex building outside the North West, we are set up to take the instruction. Send the details and we will confirm whether DSM is the right route before quoting.

Commercial EPCs in the North West →