Stroma Energy Assessors provide Overheating Analysis services, working with designers and developers to inform the design process at an early stage.

We offer simplified and CIBSE TM59 assessments for both dwellings and non-domestic buildings.

What Causes Overheating in Buildings?

Changing environmental conditions, construction techniques, and behavioural factors have led to an increased need to consider mitigation measures for preventing overheating in buildings. 


The introduction of Part O, mitigation of overheating, was introduced into the Building Regulations in 2021 to specifically address the issue in dwellings and other buildings where people sleep.


Although solvable in many cases, this is a problem that needs to be addressed at the earliest possible opportunity in the design process by undertaking an Overheating Analysis.

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Overheating Risk Analysis & Part O Compliance

Our highly skilled team of Overheating Analysis assessors can offer you expert guidance on managing potential overheating risks in your building design, ensuring a more pleasant thermal environment for the building and its occupants. Working closely with your design team, we develop robust solutions that enhance performance and comply with assessment standards.


From single dwellings to high-rise buildings, we have the expertise to formulate effective compliance strategies. If your specification doesn't meet the required limits, our seasoned assessors can provide helpful recommendations to address the issue, streamlining your submission to Building Control to keep your project on track.


We offer overheating analysis modelling to identify overheating risks, for compliance with Part O, planning requirements, as well as wider standards such as BREEAM, WELL and LEED.


Assessment of risk of overheating, is generally carried out using Dynamic Simulation Modelling (DSM) to CIBSE TM59.

What is a CIBSE TM59 Assessment?

CIBSE TM59 is an Overheating Analysis tool developed by the Chartered Institution of Building Services Engineers (CIBSE). It provides a framework to assess the potential for summertime overheating in buildings, which can be used as part of a detailed building performance assessment.


Where compliance with Part O is required and the Simplified Method cannot be used, TM59 can offer a route to this compliance.
The assessment uses measured and simulated data points to evaluate the air temperature, radiant temperature, and operative temperature of a building's space over time. From this, an Overheating Risk Index (ORI) value can be calculated to determine how likely it is for the space to experience thermal discomfort during hot weather events.


By utilising this tool, our Energy Assessors can identify and analyse any potential risks associated with your building design before construction, so your designers can make the necessary adjustments to ensure occupant comfort and energy efficiency goals are met.

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Overheating Building Regulations

With the introduction of Approved Document O into the Building Regulations, most buildings where people sleep are required to have an Overheating Analysis carried out.

This calculation is designed to ensure that the building does not become uncomfortable for occupants, especially at night. To meet these requirements, it is often necessary to implement design strategies such as providing shading or improving ventilation or other methods of removing heat from the indoor environment to reduce the risk of overheating.


Compliance with Part O can be demonstrated in 2 ways
Simplified Method, a calculation of the ratio of openable windows to floor area, or IF this does not demonstrate compliance, because this ration is less than the prescribed figure, the DSM method outlined above.


Whatever your project, the absolute rule is, consider the risk of overheating as early as possible so as not to require expensive unintended changes in design in projects to achieve compliance, causing delay and possible cost overruns.

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Click to find out more about SBEM & DSM