Building Regulations – Part O (Overheating Risk Analysis)
Keeping Homes Cool and Compliant

Overheating in buildings is becoming a growing concern, especially in urban areas where climate change and increased insulation impact indoor temperatures. Part O of the Building Regulations, introduced in June 2022, establishes new requirements to prevent excessive heat buildup in new residential buildings.

At SOCOTEC, we offer Overheating Risk Analysis to ensure compliance with Part O, using both the Simplified Method and Dynamic Thermal Modelling (TM59). Our experts provide detailed assessments and design recommendations, helping you create energy-efficient, comfortable, and sustainable living spaces.

Talk to our experts

Xavier Aguiló i Aran

Director of Sustainability / International Managing Director

xavier.aguilo@socotec.com 07703 837655

SAP & Overheating Risk Services We Offer

Overheating Risk Assessments (Part O compliance)

SAP Calculations (Part L compliance for new builds)

Simplified Method Assessments (for low-risk projects)

Dynamic Thermal Modelling (CIBSE TM59)

More Services We Offer

Energy Efficiency & Carbon Reduction Strategies

Glazing & Solar Gain Analysis

Ventilation & Cooling System Evaluations

Daylight & Thermal Comfort Assessments & Retrofitting Solutions for Existing Homes

When is Overheating Risk Analysis Required?

Early Design Stage

Helps integrate cooling strategies into design.

Planning Applications

Required for compliance with Building Regulations.

Post-Construction

Assess performance and recommend mitigation strategies.

Retrofitting Projects

Improve overheating resilience in existing homes

Sustainability & Energy Efficiency Planning

Ensure long-term thermal comfort

Understanding Overheating Risk Analysis

What is Overheating Risk Assessment?

An Overheating Risk Assessment is a desk-based study evaluating a building’s potential to overheat under different climate conditions. Under Approved Document O, overheating risk can be determined through two approaches:

1. Simplified Method

A straightforward method designed for low-risk projects, avoiding the need for complex modelling if unnecessary. This approach focuses on:

Limiting solar gains by regulating glazing area
Ensuring adequate ventilation through openings and cross-ventilation
Assessing location-specific risks (urban vs. rural environments)

2. Dynamic Thermal Modelling (CIBSE TM59)

A more detailed and accurate simulation-based approach, ideal for complex projects. This method involves:

Using dynamic simulation software to predict overheating risk
Assessing temperature thresholds based on occupancy patterns
Evaluating passive and active cooling strategies
Providing compliance evidence for regulatory approvals

While Dynamic Thermal Modelling involves higher costs, it allows for greater design flexibility, helping developers optimise cooling, ventilation, and insulation strategies for maximum comfort and efficiency.

Learn more

Part O of the Building Regulations aims to reduce overheating risks in new homes and residential buildings by setting standards for shading, ventilation, and cooling efficiency.

No, Part O regulations apply to new builds only, but we offer retrofitting solutions for improving overheating resilience in older properties.

Simplified Method – A basic compliance check focusing on solar gains and ventilation.
Dynamic Thermal Modelling (TM59) – A detailed simulation assessing overheating risks based on real-world climate conditions and building design.

Yes, if your development includes new residential dwellings or converted residential spaces, an Overheating Risk Assessment is required for Building Control approval.

Absolutely! Our experts provide full compliance reports, ensuring smooth approval for your project.

We recommend:

Optimising glazing ratios to minimise solar gain
Enhancing natural ventilation strategies
Using external shading solutions
Incorporating thermal mass to regulate indoor temperatures

Why Choose Us?

With deep expertise in Building Regulations, energy efficiency, and sustainability, we help developers, architects, and contractors navigate Part O compliance seamlessly. Whether you need initial advice, full compliance checks, or Dynamic Thermal Modelling, we ensure your project meets regulatory standards while enhancing thermal comfort and energy efficiency.

Get in touch today to discuss your Part O compliance needs!