Overheating Assessment

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Thermal Modelling Services

For Domestic & Non-Domestic Projects

At SEES, we provide affordable and reliable thermal modelling and overheating assessments for both residential and commercial buildings, using industry-leading IES Dynamic Simulation Modelling (DSM) software.

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Why do you need Overheating Assessments (Part O, CIBSE TM52 & TM59)?

With the introduction of Approved Document O (Part O) in Building Regulations, all new residential developments must now complete an Overheating Risk Assessment. Many commercial properties also require overheating assessments to comply with BREEAM criteria or specific planning conditions.

Our assessments ensure your designs minimise overheating risks and comply with:

CIBSE TM59 (Domestic Buildings)
CIBSE TM52 (Non-Domestic Buildings)
Part O – Overheating Regulations

How is Overheating Compliance achieved?

Part O outlines two compliance methods:

1. Simplified Method

This approach sets limits based on building location, glazing areas, and minimum window openings. It is straightforward but can be restrictive for certain designs.

2. Dynamic Thermal Modelling (DTM)

Using CIBSE TM59 methodology with additional Part O requirements, this detailed analysis models building performance under current and future climate conditions to ensure comfort and compliance.

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What is our Thermal Modelling Process?

Using IES DSM, our team analyses:

Solar gains and ventilation effectiveness
Internal heat gains and thermal mass impacts
Future climate scenarios (2050 projections)

We provide tailored mitigation strategies following the cooling hierarchy, including:

External shading solutions (blinds, shutters, awnings)
Optimised window sizing and orientation
Increased ceiling heights and exposed thermal mass
Natural ventilation design, including plenum windows for noise mitigation
Mechanical ventilation with heat recovery (MVHR) and tempered fresh air
Active cooling recommendations as a last resort

Why choose SEES for your Thermal Modelling?

Expertise across sectors: We conduct overheating assessments for schools, offices, residential schemes, and mixed-use developments.
Qualified thermal modellers: Our team are experienced in IES DSM, ensuring robust, compliant, and cost-effective solutions.
Full compliance support: We help you meet Part O, BB101:2018, BREEAM Hea 04, and London Plan Energy Assessment requirements efficiently.

Need an Overheating Assessment?

Whether your project is domestic or non-domestic, new build or refurbishment, SEES can deliver high-quality thermal modelling to keep your designs compliant, comfortable, and sustainable.