An early indication can help with procurement, but the accredited assessor must apply the current conventions to the actual building and fixed services.
The accredited assessor must establish the level from the actual building and fixed services. A short questionnaire can miss the feature that controls competence or software choice. This guide explains the information needed for that decision.
The level is a complexity decision
Level 3, Level 4 and Level 5 describe the competence and modelling route needed for a non-domestic energy assessment. Floor area alone does not decide the level. The building geometry, activity zoning and fixed building services must be considered together.
The current Non-Domestic EPC Conventions for England and Wales direct assessors to the assessment-level decision flowchart and accompanying notes. The result should be confirmed by an appropriately accredited non-domestic energy assessor.
Building features can change the route
Geometry and services that cannot be represented adequately by a simpler route can move the assessment to a higher level or a dynamic simulation model. The current conventions identify all atria as a Level 5 feature. Other controlling issues can sit within ventilation, heating, cooling, heat recovery and system integration.
A building that looks straightforward from the outside may still contain complex systems. Equally, a large building is not automatically Level 5.
Evidence matters as much as the label
For an existing-building EPC, the assessor needs an inspection and an evidence trail linking observations to any product, services or as-built information used. Defaults should be avoided where better evidence exists and must be justified when used.
For a new building or design-stage compliance model, the required regulatory output, approved methodology and current design information should be agreed separately. A commercial EPC and a BRUKL report are related but different outputs.
Information for an early scope
Send floor plans, sections, building use, approximate floor area and a description of the heating, cooling, ventilation, hot-water and control systems. Identify any atrium, mixed-mode strategy, night ventilation, heat recovery, district system or unusual process area.
Briary can then confirm whether the information is sufficient for a scope or whether an assessor or modeller needs a focused technical review first.
Define the output
Confirm whether the need is an existing-building EPC, a new-build Part L model, a BRUKL report or design advice.
Describe the systems
Record how each main area is heated, cooled and ventilated, including central and local equipment.
Flag unusual features
Identify atria, mixed uses, process areas, district connections and advanced ventilation or control strategies.
Confirm competence
Have the accredited assessor apply the current conventions and record the final assessment level.
Frequently asked questions
Is every office a Level 3 assessment?
No. Use class or appearance does not settle the level; the actual building and fixed services control the decision.
Does a large floor area automatically mean Level 5?
No. Size alone is not the decision rule, although a large or varied building may contain features that require a more complex route.
Is an EPC assessment level the same as an EPC rating?
No. The level describes the assessor competence and modelling complexity. The rating is the calculated energy-performance result.