Part O and TM59 Overheating Assessments
Overheating Assessment Leeds
Professional Part O and TM59 overheating assessments for new-build homes, apartments, residential conversions and glazed developments throughout Leeds and West Yorkshire.
Overheating Assessments in Leeds
One Stop Consult provides professional overheating assessments for homeowners, builders, architects and developers throughout Leeds and the surrounding West Yorkshire area.
New residential buildings can experience excessive internal temperatures where solar gains, glazing, orientation, occupancy and ventilation are not properly considered during design.
Our experienced energy consultants use approved dynamic thermal modelling software to assess overheating risk and recommend practical design improvements where required.
Overheating Assessments Across Leeds and West Yorkshire
We support projects throughout Leeds City Centre, Headingley, Horsforth, Roundhay, Chapel Allerton, Moortown, Meanwood, Pudsey, Morley, Rothwell, Garforth and Wetherby.
Nearby coverage also includes Bradford, Wakefield, Huddersfield, Dewsbury, Castleford, Pontefract, Halifax and surrounding West Yorkshire areas.
When Is One Required?
Projects That Commonly Need an Overheating Assessment
Building Control or the project SAP assessor will normally advise whether an overheating assessment is required.
Overheating Assessment Services
How We Can Support Your Leeds Project
Assessment routes are selected according to the building type, design stage and relevant Building Regulations requirements.
01
Part O Assessments
Overheating assessments for suitable new residential buildings submitted under Approved Document O.
02
TM59 Assessments
Dynamic thermal modelling based on the CIBSE TM59 methodology for residential buildings.
03
Early Design Reviews
Preliminary analysis of glazing, orientation, ventilation and shading before the architectural design is finalised.
04
Dynamic Thermal Modelling
Detailed digital modelling of internal temperatures under approved weather, occupancy and heat-gain assumptions.
05
Compliance Reporting
Clear reports prepared for Building Control and the wider project design team.
06
Remedial Design Advice
Practical recommendations where the initial model identifies an unacceptable overheating risk.
How Is the Assessment Carried Out?
The consultant creates a thermal model of the proposed building using approved dynamic simulation software.
The model considers the building design, local climate and the internal conditions expected during occupation.
Where overheating is identified, revised options can be modelled to help the design team achieve compliance.
Building orientation
Window sizes and positions
Solar gains
Ventilation strategy
Internal heat gains
Local weather data
Occupancy assumptions
Shading from surrounding buildings
Approved Document O
Part O of the Building Regulations aims to reduce the risk of overheating within new residential buildings.
The design must limit unwanted solar gains while providing an appropriate method of removing excess heat from the building.
The correct compliance route depends on the project type, location and design. More complex schemes may require dynamic thermal modelling rather than a simplified assessment.
TM59 Overheating Assessments
TM59 is the CIBSE methodology for assessing overheating risk in residential buildings using dynamic thermal modelling.
It is often used for apartments, complex residential designs and projects where detailed modelling is required to understand room-by-room performance.
The assessment considers occupied living spaces and bedrooms against the relevant TM59 criteria.
Overheating Risk Factors
What Can Increase Overheating Risk?
Large Areas of Glazing
Extensive windows can allow high levels of solar radiation into the building.
South and West-Facing Windows
These orientations can experience strong solar gains during warmer parts of the day.
Restricted Window Opening
Safety, security, noise and air-quality constraints can reduce the available natural ventilation.
High Internal Heat Gains
Occupants, lighting, appliances and communal systems can add heat to internal spaces.
Urban Heat Island Effects
Dense urban areas can remain warmer overnight and reduce the effectiveness of night cooling.
Limited External Shading
Unshaded glazing can receive direct solar exposure for long periods during summer.
Design Improvements
What Can Be Done If a Property Fails?
If the initial assessment identifies overheating risk, the consultant can model practical changes and advise on the most suitable solution for the project.
External Shading
Brise soleil, balconies, canopies and other external features can reduce direct solar gains.
Solar-Control Glazing
Glazing with improved solar-control properties can reduce the amount of heat entering the building.
Window Size Adjustments
Reducing or redistributing glazed areas can improve performance while retaining daylight and views.
Improved Natural Ventilation
Larger opening areas or more effective cross-ventilation can help remove excess heat.
Mechanical Ventilation With Summer Bypass
Suitable systems can support heat removal where natural ventilation is limited.
Alternative Ventilation Strategies
Night cooling, secure ventilation or project-specific mechanical solutions may be considered.
Ventilation Constraints and Occupant Safety
Opening windows may not always be available as the main overheating solution.
The assessment should consider whether windows can be used safely and practically during both the day and night.
External noise
Air pollution
Security risk
Fall protection
Restricted openings
Single-aspect apartments
Accessible window controls
Night-time ventilation
Our Overheating Assessment Process
We coordinate the assessment from the initial design review through to the completed report and any required revisions.
Send us the project drawings and design information.
Confirm the appropriate Part O or TM59 assessment route.
Create the dynamic thermal model.
Enter glazing, ventilation, shading and occupancy data.
Run the overheating simulations.
Review the results and identify any failing spaces.
Model improvements and issue the final report.
1
Project Review
Review the building type, drawings, location and Building Control requirements.
2
Thermal Model
Build the digital model using the proposed design and construction information.
3
Simulation
Model solar gains, internal heat, ventilation and local weather conditions.
4
Design Advice
Recommend practical improvements where overheating criteria are not achieved.
5
Final Report
Issue the completed assessment for Building Control and the project design team.
Why Choose One Stop Consult?
Our consultants regularly provide overheating assessments for developments across England and Wales.
We work closely with architects, developers, builders and homeowners to provide clear advice and practical design solutions that support Building Control compliance.
Experienced energy consultants
Approved modelling software
Part O and TM59 assessments
Fast project turnaround
Practical remedial advice
Residential development experience
Building Control support
Leeds and nationwide coverage
Information Required for a Quotation
Provide the full Leeds project address, development type, number of dwellings and current design stage.
Please upload the latest plans, elevations, sections, window schedule, ventilation strategy and construction specification.
Details of surrounding buildings, balconies, shading devices, window opening restrictions and external noise constraints are also helpful.
Related Leeds Services
Other Services Your Project May Require
Important Overheating Assessment Information
Results depend on the accuracy of the drawings, glazing, ventilation, shading, occupancy and construction information provided. Changes made after the assessment can affect compliance and should be referred back to the consultant.
The assessment predicts performance using approved modelling assumptions and does not guarantee the exact temperature experienced in every future condition. One Stop Consult provides consultancy and coordination support through experienced energy and overheating assessment specialists.
Frequently Asked Questions
Overheating Assessment Leeds FAQs
What is Part O?
Part O is the section of the Building Regulations that aims to reduce overheating risk in new residential buildings.
What is TM59?
TM59 is the CIBSE methodology for assessing overheating in residential buildings using dynamic thermal modelling.
Is an overheating assessment always required?
No. It depends on the development, location, design and chosen compliance route. Building Control or the SAP assessor will normally advise.
Can you help if the design fails?
Yes. The consultant can model practical changes such as shading, glazing and ventilation improvements.
How long does an assessment take?
Most assessments can be completed within a few working days once all required information has been received.
Does large glazing increase the risk?
It can. Window size, orientation, solar-control properties and shading all influence solar heat gains.
Can open windows be used as the solution?
Sometimes, but noise, security, pollution, fall risk and opening restrictions must also be considered.
Do you cover all of Leeds?
Yes. We provide overheating assessments throughout Leeds, West Yorkshire and the wider West Yorkshire.
What information is needed for a quotation?
Provide the address, project type, plans, glazing details, ventilation strategy and any relevant Building Control requirements.
Request Your Free Overheating Assessment Quote
Complete the form below with the Leeds project address, development type and current design stage. Upload the latest drawings, glazing information and ventilation strategy so our team can review the requirement and provide an appropriate quotation.