Specialist service
TM59 Overheating Assessments Scotland
TM59 overheating assessments for residential design teams in Scotland. We model room conditions and test mitigation options so the project can address overheating risks while the design is still adaptable.
From £200 + VAT
Starting price for straightforward assessments. Final pricing depends on property size, complexity, available information and site requirements. We confirm the scope and full cost before work begins.
What is included
What you get with this service
A clear, practical scope covering the assessment, technical work and final outputs needed for the project.
Who this is for
Designed for the teams responsible for delivery and compliance
We work directly with the people who need clear answers, dependable reporting and a straightforward route to completion.
Last reviewed: . Reviewed against the official and technical sources below.
What is a TM59 assessment?
CIBSE TM59 provides a methodology for assessing overheating risk in homes through dynamic thermal modelling. It considers conditions in occupied rooms using defined criteria and assumptions. It is different from an EPC, which addresses energy performance rather than room-by-room summer comfort.
Is TM59 a legal requirement for every Scottish home?
No blanket claim should be made. TM59 is a technical methodology; whether it is requested depends on the applicable Scottish standards, planning conditions and project brief. England’s Part O requirements should not be presented as Scottish law. Agree the required compliance evidence with the design team and relevant authority.
What affects the assessment?
Glazing area and solar performance, orientation, shading, ventilation openings, thermal mass, occupancy and internal gains all influence results. Window opening assumptions should reflect practical restrictions such as safety, noise and security. A model based on unrealistic ventilation assumptions can mislead a design decision.
How is the modelling carried out?
The scope establishes rooms to assess, weather data, occupancy assumptions and the applicable methodology. A baseline model is tested, then agreed changes are compared. The report should describe the assumptions, results, any criteria not met and the mitigation measures assessed.
What mitigation can be tested?
Options can include adjusting glazing, adding external shading and revising the ventilation strategy. Compare feasible passive measures early with the architect and services engineer. A successful modelled option must still be incorporated into the actual design and used as assumed.
When should I arrange it?
Commission the assessment before glazing, facade and ventilation specifications are fixed. Provide the design issue date and identify constraints so mitigation testing addresses options that can actually be built. Update the model if significant design changes affect the assessed assumptions.
What information should I send?
- Plans, elevations, sections and site orientation
- Glazing g-values, frame/opening dimensions and shading geometry
- Room uses, occupancy assumptions and internal gains
- Ventilation strategy and restrictions on window opening
- Construction build-ups, design stage and the assessment brief
Send what you have through our quote request form or contact the Glasgow team to confirm the scope. See our selected projects for the buildings and estates featured in our portfolio.
Related assessments
Official guidance and sources
Requirements depend on the property, proposed work and relevant dates. The sources below distinguish statutory guidance from assessment methodology; SES provides assessment services, not regulatory approval.
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Send us the project details and we will confirm the scope.
Share the property type, location, project stage and target date. We will come back with the information we need and the next available delivery window.
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