Find out how Vision Energy can take care of all your compliance needs for your new Build Project
Vision Energy can take care of your energy assessments for your conversion project, find out more today
All Extensions with 25% or more glazing compared to the floor area require SAP & EPC assessment and calculations, find out more
During the design of your project, it is important to ensure that not only the dwelling is insulated well but also does not overheat across the year. Overheating assessment may be required to design around non-compliance overheating issues, as part of planning permission or as part of an energy statement.
Overheating risk has become a critical consideration in UK building design. As summer temperatures rise and building fabric performance improves, managing internal comfort is no longer secondary to energy efficiency. Demonstrating compliance through robust overheating analysis is now a core requirement under Building Regulations and planning policy.
Vision Energy provides professional overheating analysis services across the UK, supporting residential, commercial and educational developments. Our assessments are undertaken in accordance with Approved Document Part O, CIBSE TM59, TM52 and BB101 guidance using dynamic thermal modelling to evaluate risk and inform design decisions.
Overheating analysis assesses the risk of excessive internal temperatures during warmer months. Unlike steady state calculations, dynamic thermal modelling simulates how a building responds over time to solar gains, internal heat gains, ventilation rates, fabric performance and occupancy patterns.
Approved Document Part O requires new residential buildings to demonstrate that overheating risk has been addressed. While simplified assessment routes exist, dynamic modelling in accordance with TM59 provides a more robust and transparent method of compliance, particularly for complex or highly glazed schemes.
For non residential projects, CIBSE TM52 applies adaptive comfort criteria to assess temperature exceedance. Educational buildings follow BB101 guidance, which sets specific thermal comfort and ventilation requirements for classrooms and learning environments.
By modelling real design inputs and current weather data sets, overheating analysis provides clear evidence that internal comfort thresholds will not be exceeded under typical summer conditions.
Posted10th February 2026
Posted31st October 2025
Posted1st October 2025
Vision Energy are a leading Sustainability & Energy consultancy working nationwide. We specialise in calculations & reports covering Building Regulations, Planning Permission and all other sustainability or energy needs within the construction sector. With a vast amount of knowledge and experience having worked on thousands of projects across the UK one of our engineers would be more than happy to assist you on your project. SAP Calculations | SBEM Calculations | Energy Statements | BREEAM Pre-Assessments | M&E Design | EPC's | Water Efficiency | Air Permeability
Part O focuses on residential overheating risk and is now mandatory under the Building Regulations. Compliance is commonly demonstrated through TM59 modelling, which evaluates factors such as the number of hours above adaptive comfort thresholds and night time temperature control within bedrooms.
TM52 applies to non residential buildings and uses adaptive comfort theory to assess the extent and duration of temperature exceedance. It is often used for offices, mixed use developments and commercial spaces where occupant comfort must be demonstrated.
BB101 is specific to educational buildings and incorporates criteria tailored to classroom occupancy patterns, internal heat gains and ventilation strategies. Overheating analysis for schools requires particular care in modelling realistic use scenarios and ventilation performance.
Understanding the distinction between these standards ensures that assessments are correctly scoped and aligned with project requirements.
Our overheating assessments begin with a detailed review of architectural drawings, glazing ratios, façade design and ventilation strategies. Key inputs such as occupancy profiles, equipment loads and local weather data are incorporated into a dynamic thermal model.
Simulations are carried out to evaluate temperature performance across representative spaces and orientations. Where risk is identified, we provide clear and proportionate recommendations that may include adjustments to shading, glazing specification, ventilation design or façade configuration.
Reports are structured for submission to Building Control or planning authorities and clearly demonstrate compliance with Part O, TM59, TM52 or BB101 as required.
Overheating compliance should not be approached as a late stage check. Introducing dynamic thermal modelling during concept or developed design stages allows teams to understand how orientation, glazing strategy and ventilation approach influence internal comfort.
Early assessment reduces the risk of redesign, supports planning submissions and strengthens the overall sustainability narrative of a project. It also ensures that measures introduced to improve airtightness and energy efficiency do not inadvertently increase summer overheating risk.
As buildings become more efficient and climate conditions continue to evolve, overheating analysis is increasingly central to responsible design.
Overheating Assessment in UK Building Design: Managing Excessive Glazing to Meet Part O Regulations
In recent years, overheating in buildings has become a significant issue, particularly in...
As of Wednesday the 15th of June 2022 the new Approved Documents L (conservation of fuel and power) and O (Overheating), have come into force.
The changes have been in the process for a...
Building Regulations Part O was introduced in June 2021 to tackle the growing problem of overheating in new residential buildings. As...
Part O? Overheating Assessment? Dynamic simulation modeling? all very familiar words for a building physics and sustainability consultant, however since the new Part O of Building Regulations has...
Creating a safe, comfortable, and well-ventilated environment in schools is more important than ever. Whether you’re managing a new school construction project or upgrading an...
Vision Energy were commissioned in 2021 to undertake an assessment in conjunction with fabric and mechanical upgrades to multiple blocks on the campus. The works consisted of external wall...
The proposed project consists of a café and bike workshop located on the land off Newmarket Road near Barnwell Lake, the café is to be a cycle-themed café across a single storey building. The...
Vision were delighted to be part of the team to prepare this scheme for planning. A Multi-Residential & Commercial scheme in London. We provided an Energy & Sustainability statement incorporating...
A number of guides and standards are available for the assessment of overheating in buildings. CIBSE guides TM59 covers overheating in residential buildings. CIBSE TM52 covers overheating in commercial buildings. BB101 covers overheating in educational buildings.
Overheating assessments will cover a number of weather scenarios specifically to the location of the building/development. both current and future weather will be considered as well as different weather patterns such as;
A number of factors can impact the internal temperatures of a building but below are a few key factors
All of the above can contribute to a building overheating as they will raise the internal temperatures unless correctly designed and considered.
Each overheating assessment is unique to the development so the route to limit overheating is different for each assessment. however, the below outlines some mitigation strategies against overheating;
Overheating assessments are bespoke to each project/building so the pricing is not fixed, however, the cost can vary between £250 to £1000+. If you would like an accurate fee for your overheating assessment get in touch with our team.