Overheating Assessments
As buildings become more airtight to meet Part L of the Building Regulations, maintaining a comfortable indoor temperature becomes a challenge. Overheating can occur if thermal comfort isn't properly balanced, resulting in uncomfortable living or working conditions that harm health and productivity.
Without a thorough overheating risk analysis, your project may fail to comply Part O of the Building Regulations and other planning requirements, putting your planning approval at risk and potentially causing costly delays. Overheating not only affects comfort but also increases energy consumption and operational costs, further impacting the building’s efficiency.
An overheating assessment helps identify risks early, ensuring Part O compliance and streamlining planning approvals. By implementing bespoke, cost-effective solutions, you can optimise thermal comfort, reduce energy use, and create a more sustainable, comfortable building.
What is an overheating assessment?
An overheating assessment is a detailed evaluation that identifies and addresses the risk of high indoor temperatures, ensuring buildings remain thermally comfortable, even during hot weather. By assessing the building’s design and key elements impacting its thermal performance, the assessment ensures that residents or occupants can enjoy a comfortable, healthy environment all year round.
Key factors evaluated in an overheating assessment include:
- Building Orientation: The direction a building faces impacts the solar heat from sun exposure, which increases indoor temperatures.
- Glazing and Window Design: The size, specification, and placement of windows determine the amount of solar heat entering the space.
- Shading Devices: Internal and external shading, like blinds, curtains, and overhangs, help manage solar gain and reduce overheating risks.
- Ventilation Strategies: The effectiveness of natural or mechanical ventilation in providing adequate airflow and cooling.
- Thermal Mass: The ability of floors, walls and ceilings to absorb and store heat plays a key role in maintaining thermal stability.
- Occupant Behaviour: How occupants use and occupy spaces can influence temperature levels inside the building.
Part O Overheating Assessment for New Build Residential Development
Part O compliance is mandatory for all new residential buildings to ensure effective solar gain control and efficient heat removal, promoting thermal comfort and preventing overheating. Compliance can be demonstrated through either the Simplified Method or Dynamic Thermal Modelling Method, depending on your project's complexity. MACH can guide you in selecting the most suitable approach to achieve Part O compliance for your new development.
Simplified Method
The Simplified Method provides an initial overheating risk assessment based on factors like building orientation, window size, and shading devices. It is ideal for standard, low-complexity buildings without extensive glazing or those located in areas with a lower risk of overheating. This approach offers a quick, cost-effective solution to determine whether a more detailed assessment is required for your project to ensure compliance with Part O and prevent overheating.
Dynamic Thermal Modelling (CIBSE TM59 Methodology)
For more complex building designs, extensive glazing, or developments in areas at higher risk of overheating, the Dynamic Thermal Modelling method is required. Using the TM59 methodology, advanced 3D modelling software simulates the building's thermal performance under various weather conditions, accounting for factors such as solar gain, thermal mass, ventilation strategies, and occupancy patterns. This detailed analysis provides a more accurate assessment and identifies effective overheating mitigation strategies to achieve Part O compliance.
Overheating Assessment for Non-domestic Development
The issue of overheating affects more than just new residential developments. Commercial buildings, schools, and other properties with large glazed areas are also prone to uncomfortable and unsafe indoor temperatures during the warmer months. MACH offers Dynamic Thermal Modelling for all building types, providing practical solutions that meet planning requirements and performance targets such as BREEAM, BB101 & Technical Annex 2F. Our expertise ensures that your building remains comfortable, energy-efficient, and fully compliant with all overheating requirement, helping you create sustainable, healthy indoor environments for occupants.
Why Choose MACH for Your Overheating Assessment and Thermal Comfort Solutions?
At MACH, we don't just focus on overheating in isolation — we take a holistic approach to overheating risk assessment, balancing thermal comfort, daylight performance, energy use, and acoustics to identify the ‘sweet spot’ where your building performs at its best.
MACH will work with any site but we particularly like challenging, noisy sites, where with our team of acoustic consultants we specialise in low cost and low carbon ventilation solutions for overheating.
Our skilled staff are able to provide quick and detailed overheating assessments with a pragmatic approach, offering advice on how to improve your design when needed.
Our team of friendly engineers are more than happy to answers any questions you have about your project.
FAQ
-
All proposed new-build residential developments will need an overheating assessment to demonstrate compliance with Part O.
For non-domestic buildings, overheating assessments may be required due to planning conditions, BREEAM certification, or other relevant design guidelines. -
The overheating assessment should be carried out early in the design phase of your building project, ideally before detailed design work begins. This allows time to make any necessary adjustments to ensure Part O compliance and avoid costly delays later in the process. MACH always recommend carrying out the assessment before carrying out a planning application, as the results of the assessment could change the design of your building.
-
The time required for an overheating assessment can vary depending on the complexity of the project. For standard developments, the process typically takes 5 – 15 working days. More complex projects may take longer, particularly if multiple revisions are needed.
-
The cost of an overheating assessment varies based on the size and complexity of the building however MACH offer overheating assessments from as little as £150. Get in touch so MACH can provide a tailored quote based on your specific project needs.
-
To ensure an accurate and thorough assessment, we require the following information:
- Site plan
- Floor plans
- Elevations
- Sections
- External construction specifications and U-values
- Window U-values and g-values (we can advise what helps to achieve compliance)
- Heating/cooling system specification
- Ventilation specification (we can advise if mechanical ventilation is required)
-
If your building fails to comply with Part O regulations, MACH will help you explore low carbon natural ventilation solutions and other strategies to reduce overheating. We will guide you through the necessary changes to ensure compliance while maintaining building efficiency and comfort, also consider cost and build practicalities.