At CIBSE TM59 Overheating Assessments, we deliver fully compliant modelling reports to support Part O of the Building Regulations and planning applications.

Since compliance with Part O of the Building Regulations is now mandatory, early-stage TM59 analysis helps avoid costly design changes later.

As overheating affects both occupant wellbeing and regulatory approval, our modelling ensures buildings perform safely without unnecessary reliance on mechanical cooling.

Get your free TM59 overheating assessment in Warwickshire quote today.

What Is a CIBSE TM59 Overheating Assessment in Warwickshire ?

A TM59 assessment in Warwickshire uses dynamic thermal modelling software to simulate indoor temperatures across different spaces in a residential property.

It evaluates the internal environment based on detailed construction data, window performance, solar shading, occupancy, and ventilation.

The simulation is measured against two key criteria: the number of hours living spaces exceed 26°C, and the frequency of overheating in bedrooms during the night.

If either of these thresholds is breached, the dwelling is considered at risk of overheating.

Since overheating directly impacts health, comfort, and regulatory compliance, a TM59 assessment provides vital evidence that the design is fit for purpose.

How Much Does a TM59 Assessment Cost?

The cost of a CIBSE TM59 overheating assessment is from £500 to £2,000.

The cost depends on the number of dwelling types, building complexity, and whether it is combined with SAP, BREL, or energy assessments.

Larger schemes or developments with varied layouts may require more simulation time, while small schemes with a limited number of representative units will fall at the lower end of the range.

As overheating risk affects compliance, we provide clear, fixed quotes following a design review.

When Is a TM59 Assessment in Warwickshire Required?

A CIBSE TM59 assessment in Warwickshire is required for new residential developments where overheating risk is a concern.

It is most commonly requested for projects in urban areas, south-facing plots, or dense developments with limited airflow and solar shading.

Planning authorities and frameworks such as London Plan Policy SI4, Building Regulations Part O, and BREEAM HEA 04 may require TM59 analysis to demonstrate comfort and safety.

As regulations now place greater emphasis on passive cooling and thermal resilience, TM59 is a standard part of many residential design submissions.

What Is Included in a TM59 Assessment in Warwickshire?

A TM59 overheating assessment in Warwickshire includes a full thermal simulation of each representative dwelling type using hourly weather data across the summer months.

The assessment considers the building’s thermal mass, insulation, window sizes, orientation, natural ventilation, and internal heat gains.

It uses Design Summer Year (DSY) weather files to simulate realistic future climate scenarios, including DSY1 for standard risk and DSY2/3 for more extreme events.

The model evaluates both living areas and bedrooms to ensure daytime and night-time comfort.

Since residential spaces are used for rest and recovery, achieving low risk of overheating is essential to occupant health and wellbeing.

What Are the Benefits of TM59 Overheating Assessments?

CIBSE TM59 assessments help developers and design teams meet comfort, compliance, and sustainability goals.

Key benefits include:

• Ensures compliance with Building Regulations Part O and planning policies
• Identifies overheating risks early in the design process
• Supports passive cooling and low-energy design strategies
• Helps achieve BREEAM credits and meet London Plan requirements
• Reduces future risk of retrofit cooling systems or resident complaints
• Informs decisions on glazing, shading, ventilation, and layout
• Demonstrates commitment to climate resilience and occupant wellbeing

How Long Does a TM59 Assessment Take?

Most TM59 assessments are completed within 5 to 10 working days, provided that all architectural drawings, specifications, and ventilation strategies are available.

We also offer accelerated turnaround for planning submissions and time-sensitive projects.

Since overheating risk can be design-sensitive, early modelling helps reduce the need for costly adjustments later.

Is a TM59 Assessment in WarwickshireRequired for Every Dwelling?

A TM59 assessment in Warwickshire typically uses representative dwelling types to simulate performance across the development.

This means homes with similar layouts, orientations, glazing, and ventilation strategies can be grouped together under a single simulation.

Since this approach reduces modelling time and still meets compliance standards, it’s widely accepted by planning authorities and certification bodies.

What Weather Files Are Used in a TM59 Assessment in Warwickshire?

TM59 assessments in Warwickshire use Design Summer Year (DSY) weather files, which reflect realistic summer conditions over a 30-year period.

The most commonly used file is DSY1, based on moderately warm conditions, but for higher-risk sites or future-proofing, DSY2 and DSY3 can also be used.

Because these files simulate future climate impacts, they help ensure the building remains comfortable in coming decades.

How Is Overheating Defined in TM59?

Overheating is defined based on two key metrics.

Living spaces should not exceed 26°C for more than 3% of annual occupied hours.

Bedrooms should avoid extended periods over 26°C during night-time hours to ensure restful sleep.

Since these thresholds are linked to health and comfort, meeting them is essential for occupant wellbeing and regulatory approval.

Can TM59 Be Used with SAP or BREEAM Assessments?

TM59 is often carried out alongside SAP calculations for new homes and supports BREEAM HEA 04 thermal comfort credits.

It can also be combined with Part O overheating assessments, helping streamline the compliance process.

As these services rely on similar inputs and software platforms, bundling them saves time and improves consistency across reports.

What Happens If My Building Fails the TM59 Assessment?

If your design fails to meet TM59 comfort criteria, we will provide clear, practical recommendations to improve performance.

These may include increasing window openings, adding solar shading, adjusting ventilation strategies, or reducing internal heat gains.

Since early design-stage changes are easier to implement, we recommend running the assessment before planning submission or detailed design finalisation.

Is TM59 Accepted as Proof of Compliance with Part O?

TM59 dynamic modelling is an accepted method for demonstrating compliance with Part O of the Building Regulations in England.

It provides a more flexible and performance-based alternative to the simplified method, particularly for homes with larger glazing areas or limited cross-ventilation.

As Part O requires evidence of thermal performance, a TM59 report is often the most robust and future-proof option.

What Types of Residential Projects Need TM59 Assessments?

TM59 assessments are required for new-build residential schemes, particularly in urban, high-density, or mixed-use developments.

They are also commonly used in student accommodation, care homes, apartment blocks, and housing schemes where natural ventilation is relied upon.

Since these buildings often have limited external shading or cross-ventilation, overheating risk must be modelled to satisfy planning and compliance requirements.

Can You Carry Out TM59 Assessments for High-Rise Flats?

We provide TM59 assessments for high-rise and multi-residential buildings, including blocks with varied layouts and orientations.

Each representative floor or unit type is modelled based on height, glazing ratio, and shading context.

As upper-floor flats are especially prone to overheating, accurate simulation helps prevent future performance issues and ensures occupant comfort.

Does TM59 Apply to Refurbishments or Extensions?

TM59 is primarily intended for new residential buildings, but it may also apply to large-scale refurbishments where the internal layout or ventilation strategy is significantly altered.

For extensions or minor renovations, a simplified overheating risk assessment may be more appropriate.

As each case is different, we review the scope of works to recommend the right level of assessment.

What Ventilation Strategies Are Considered in TM59?

TM59 assessments can account for a range of ventilation strategies, including natural ventilation (opening windows), mechanical extract, and mixed-mode systems.

The modelling evaluates how effectively the strategy removes heat from internal spaces during the day and night.

As effective ventilation is key to comfort, clear specification of window sizes, control methods, and airflow rates is essential.

Can You Model Future Climate Scenarios in TM59?

We can model future overheating risk using future weather files that reflect climate change projections from UKCP09 or UKCP18.

This is especially useful for schemes aiming to meet long-term performance goals, BREEAM requirements, or resilience targets set by local authorities.

Since climate change is increasing summer temperatures, many projects now include future-proofing as standard.

Do Local Authorities Accept TM59 Reports?

Local authorities across the UK widely accept TM59 assessments as part of planning applications.

Many urban planning departments, including those governed by the London Plan, require TM59 modelling to demonstrate that new homes will be thermally comfortable without relying on mechanical cooling.

Since the method is supported by CIBSE and recognised in national guidance, it is a trusted tool for showing design compliance.

How Do I Book CIBSE TM59 Overheating Assessments in Warwickshire?

Get in touch with us at CIBSE TM59 overheating analysis in Warwickshire for our online form for accurate, fast, and planning-compliant overheating assessments for residential developments. 

We provide detailed thermal comfort modelling that supports healthy, resilient, and regulation-ready homes.

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