Typical appointments
- New dwellings and residential developments in England
- Early facade, glazing and ventilation design
- Changes to window openings, shading or internal layouts
- Coordination of passive measures and active cooling proposals
Energy and compliance
Part O overheating assessment
Residential overheating risk considered alongside glazing, shading, ventilation, security and energy strategy.
Service overview
Assessment connected to design decisions
Overheating design decisions affect architecture and MEP systems. MEPX can coordinate the assessment inputs with glazing, shading, openable areas, ventilation strategy and any proposed active cooling.
The aim is to identify risks while practical design options remain available and to maintain a clear assumptions and evidence trail.
Scope note Applicable assessment, evidence, lodgement and third-party responsibilities are confirmed for each commission.
Project fit
When the service is useful
Information to begin
- Plans, elevations, sections and orientation
- Window sizes, opening areas and glazing data
- External shading and surrounding context
- Ventilation, security and noise constraints
Technical scope
Outputs and design considerations
Typical deliverables
- Assessment scope and inputs schedule
- Overheating assessment outputs
- Risk summary and design recommendations
- Updated evidence as the design develops, where appointed
Design considerations
- Solar gain, glazing and orientation
- Shading and usable opening areas
- Purge ventilation, noise and security
- Interaction with Part L and active cooling
Common questions
Before commissioning the work
What does Part O address?
Approved Document O addresses overheating risk in new residential buildings in England. The applicable assessment route depends on the building and design.
When should overheating be assessed?
Assessment should begin while glazing, orientation, shading, ventilation openings and internal layouts can still be coordinated.
Is air conditioning the default solution?
No. Passive measures and usable ventilation should be considered first. Any active cooling proposal needs to be coordinated with the wider energy and MEP strategy.
What information is normally required?
Typical inputs include geometry, orientation, glazing, shading, opening details, ventilation strategy, location and relevant occupancy assumptions.
Project discussion
Confirm the assessment route early
Share the building type, location, design stage and available information. MEPX can identify the likely assessment scope and information needed to proceed.