Consider summer comfort while the design can change
Large areas of glazing, orientation, shading and ventilation all matter when considering overheating. Dynamic simulation modelling (DSM) allows the design to be assessed over time rather than relying on a single room temperature. Early discussion is useful when window layouts and shading details are still being developed.
What the assessment covers
Dynamic simulation modelling evaluates how a building responds to weather, solar gains and ventilation. For Part O projects in England, the dynamic thermal modelling route uses CIBSE TM59 with the requirements set out in Approved Document O.
Useful starting information: drawings, orientation, glazing specification, shading and ventilation strategy.
Part O guidance — England ↗Give the model a realistic ventilation strategy
Send opening dimensions and explain practical constraints on how windows can be used. Noise, security and restricted openings may affect the proposed strategy. Identify external obstructions and shading, and distinguish existing decisions from options you want reviewed. Part O guidance referenced here applies to England; the appropriate brief for other UK locations is agreed separately.
Your questions
Is a SAP calculation also an overheating assessment?
They address different questions. Tell us if your project needs both an energy assessment and a separate overheating assessment so the scopes can be coordinated.
When should I request the assessment?
Preferably while glazing, shading and ventilation choices can still be adjusted. If the design is already fixed, send the current drawings and any restrictions on changes.
Building regulations and assessment routes differ across the UK. Project location, the applicable requirements and deliverables are confirmed when agreeing the scope.