CIBSE TM59
Standard
Design Methodology for the Assessment of Overheating Risk in Homes
Application area
Residential overheating
Project relevance
Bedroom and living room overheating criteria for UK residential planning compliance.
Sustainability engineering
Building performance for comfort, health and efficiency
Thermal comfort, indoor air quality, overheating risk and operational energy assessment supporting design decisions and post-occupancy verification.
Service scope
Building performance engineering at SEINZEN assesses how buildings perform for occupants and operators — not just how they comply on paper. Analysis covers thermal comfort, indoor air quality, daylight, acoustics and overheating risk using dynamic simulation and established assessment methodologies.
Design-stage analysis identifies overheating risk in naturally ventilated and mixed-mode buildings using CIBSE TM59, TM52 and dynamic simulation before glazing and ventilation strategies are fixed. Post-occupancy evaluation compares operational performance against design predictions.
Indoor environmental quality assessment covers CO₂ concentration, ventilation effectiveness, thermal comfort indices and pollutant exposure for office, healthcare and educational occupancies. Results inform HVAC system selection, control strategies and operational setpoints.
Performance outcomes are communicated to design teams with clear recommendations — not just compliance checklists. Lifecycle performance considerations including maintenance, adaptability and operational energy are integrated into assessment scope.
Key engineering capabilities
Overheating risk assessment
CIBSE TM59, TM52 and dynamic simulation analysis for residential and non-residential overheating compliance.
Thermal comfort analysis
PMV, PPD and adaptive comfort model assessment for occupied spaces across seasonal conditions.
Indoor air quality assessment
Ventilation effectiveness, CO₂ modelling and pollutant exposure analysis for health and productivity.
Daylight and glare analysis
Daylight factor, useful daylight illuminance and glare probability assessment for visual comfort.
Post-occupancy evaluation
Operational performance comparison against design predictions with occupant feedback integration.
Energy benchmarking
Operational energy comparison against design model, certification targets and sector benchmarks.
Facade performance optimisation
Glazing, shading and insulation trade-off analysis for thermal, daylight and energy performance.
Natural ventilation design support
Airflow network modelling and opening strategy design for mixed-mode and passive ventilation buildings.
WELL and certification support
Indoor environmental quality credit documentation for WELL, BREEAM and LEED certification pathways.
Design and delivery methodology
- 01
Performance criteria definition
Comfort, IAQ and overheating criteria established per occupancy type, certification targets and client brief.
- 02
Baseline assessment
Initial simulation with architectural and MEP inputs to identify performance gaps and risk areas.
- 03
Design iteration support
Parametric analysis of envelope, shading and system alternatives with comparative performance reporting.
- 04
Compliance verification
Overheating, ventilation and comfort compliance documentation for planning and certification submission.
- 05
Design integration
Performance recommendations communicated to architectural and MEP teams for design incorporation.
- 06
Post-occupancy verification
Operational monitoring, occupant survey and performance comparison against design-stage predictions.
Technical design criteria
CIBSE TM59 overheating criteria
Bedroom and living room overheating hours for residential developments per CIBSE TM59 methodology.
CIBSE TM52 operative temperature
Three-criteria overheating assessment for non-residential naturally ventilated and mixed-mode buildings.
Adaptive thermal comfort
ASHRAE 55 and EN 16798 adaptive model application for naturally ventilated space comfort assessment.
CO₂ concentration modelling
Ventilation rate verification against occupancy-driven CO₂ targets for indoor air quality compliance.
Useful daylight illuminance
UDI 100–3000 lux assessment for daylight autonomy and glare risk in workspace design.
Solar shading optimisation
External shading, brise-soleil and glazing specification trade-offs for solar gain control.
Thermal bridging assessment
Linear thermal transmittance and point heat loss analysis for envelope performance accuracy.
Airflow network modelling
Natural ventilation flow paths, stack effect and wind pressure modelling for opening design.
Operational energy gap analysis
Comparison of metered consumption against design model predictions with variance investigation.
Acoustic performance integration
Noise criteria coordination with thermal and ventilation design for openable window strategies.
Engineering principles and calculation approaches
PMV = f(M, W, Icl, tr, ta, va, pa)
Variables
PMV = predicted mean vote; M = metabolic rate; W = external work; Icl = clothing insulation; tr = mean radiant temp; ta = air temp; va = air velocity; pa = water vapour pressure
Application
Thermal comfort assessment per ISO 7730 for mechanically conditioned spaces.
Notes
PMV between −0.5 and +0.5 indicates acceptable comfort for most occupants.
PPD = 100 − 95 × exp(−0.03353 × PMV⁴ − 0.2179 × PMV²)
Variables
PPD = predicted percentage dissatisfied (%); PMV = predicted mean vote
Application
Percentage of occupants expected to find thermal conditions unacceptable.
Notes
PPD ≥ 10% at PMV = ±0.5; minimum PPD of 5% at PMV = 0.
T_comfort = 0.31 × T_running_mean + 17.8
Variables
T_comfort = comfort temperature (°C); T_running_mean = exponentially weighted running mean outdoor temperature (°C)
Application
Adaptive comfort temperature for naturally ventilated buildings per ASHRAE 55.
Notes
Apply 2.5°C and 3.5°C comfort bands for 80% and 90% acceptability respectively.
CO₂ = CO₂_outdoor + (N × G) / Q
Variables
CO₂ = indoor concentration (ppm); CO₂_outdoor = outdoor level (ppm); N = occupancy; G = CO₂ generation rate (L/s·person); Q = ventilation rate (L/s)
Application
Steady-state CO₂ concentration estimation for ventilation rate verification.
Notes
Dynamic modelling preferred for variable occupancy; 800–1000 ppm typical office target.
Performance_gap = (E_measured − E_predicted) / E_predicted × 100
Variables
Performance_gap = operational gap (%); E_measured = metered consumption; E_predicted = design model prediction
Application
Post-occupancy energy performance gap quantification for investigation.
Notes
Normalise for weather, occupancy and operational schedule differences before comparison.
Final design values must be determined using project-specific inputs, applicable standards, manufacturer data and engineering judgement.
BIM, Revit and integrated design
Architectural Revit models provide geometry, glazing properties and shading data for performance simulation model construction.
Space boundaries and zone assignments from BIM models feed thermal and airflow simulation with manual verification of critical inputs.
Performance analysis results are linked to model spaces through colour-coded visualisation supporting design team review sessions.
Post-occupancy monitoring sensor locations are coordinated with BIM model space references for data mapping.
International standards and codes
CIBSE TM52
Standard
The Limits of Thermal Comfort: Avoiding Overheating in European Buildings
Application area
Non-residential overheating
Project relevance
Three-criteria overheating assessment for commercial and institutional buildings.
ISO 7730
Standard
Ergonomics of the Thermal Environment
Application area
Thermal comfort
Project relevance
PMV and PPD calculation methodology for thermal comfort assessment.
ASHRAE 55
Standard
Thermal Environmental Conditions for Human Occupancy
Application area
Thermal comfort
Project relevance
Comfort temperature ranges, adaptive model and acceptability criteria.
EN 16798-1
Standard
Indoor Environmental Input Parameters
Application area
Indoor environmental quality
Project relevance
Category I–IV indoor environmental criteria for design and assessment.
WELL Building Standard
Standard
Air, Thermal Comfort and Light Features
Application area
Certification
Project relevance
Performance-based IEQ credits for WELL certification pathway.
LEED v4.1
Standard
Indoor Environmental Quality Credits
Application area
Certification
Project relevance
Thermal comfort, daylight and air quality credit requirements.
BREEAM Hea 04
Standard
Thermal Comfort Credit
Application area
Certification
Project relevance
Thermal modelling and comfort verification for BREEAM assessment.
CIBSE TM40
Standard
Health Issues in Building Services
Application area
Indoor air quality
Project relevance
Health-related indoor environmental parameters and ventilation requirements.
EN 17037
Standard
Daylight in Buildings
Application area
Daylight assessment
Project relevance
Daylight provision, exposure to sunlight and view out criteria.
BSRIA Soft Landings
Standard
Operational Performance Framework
Application area
Post-occupancy
Project relevance
Aftercare and post-occupancy evaluation framework for performance verification.
CIBSE Guide A
Standard
Environmental Design
Application area
Design criteria
Project relevance
Internal design conditions and environmental criteria for building services design.
| Code | Standard | Application area | Project relevance |
|---|---|---|---|
| CIBSE TM59 | Design Methodology for the Assessment of Overheating Risk in Homes | Residential overheating | Bedroom and living room overheating criteria for UK residential planning compliance. |
| CIBSE TM52 | The Limits of Thermal Comfort: Avoiding Overheating in European Buildings | Non-residential overheating | Three-criteria overheating assessment for commercial and institutional buildings. |
| ISO 7730 | Ergonomics of the Thermal Environment | Thermal comfort | PMV and PPD calculation methodology for thermal comfort assessment. |
| ASHRAE 55 | Thermal Environmental Conditions for Human Occupancy | Thermal comfort | Comfort temperature ranges, adaptive model and acceptability criteria. |
| EN 16798-1 | Indoor Environmental Input Parameters | Indoor environmental quality | Category I–IV indoor environmental criteria for design and assessment. |
| WELL Building Standard | Air, Thermal Comfort and Light Features | Certification | Performance-based IEQ credits for WELL certification pathway. |
| LEED v4.1 | Indoor Environmental Quality Credits | Certification | Thermal comfort, daylight and air quality credit requirements. |
| BREEAM Hea 04 | Thermal Comfort Credit | Certification | Thermal modelling and comfort verification for BREEAM assessment. |
| CIBSE TM40 | Health Issues in Building Services | Indoor air quality | Health-related indoor environmental parameters and ventilation requirements. |
| EN 17037 | Daylight in Buildings | Daylight assessment | Daylight provision, exposure to sunlight and view out criteria. |
| BSRIA Soft Landings | Operational Performance Framework | Post-occupancy | Aftercare and post-occupancy evaluation framework for performance verification. |
| CIBSE Guide A | Environmental Design | Design criteria | Internal design conditions and environmental criteria for building services design. |
Applicable standards depend on the project location, building use, authority having jurisdiction, employer requirements and contract documents. The current adopted edition must be confirmed at the beginning of each project.
Project deliverables and documentation
Performance assessment scope
Analysis objectives, criteria, methodology and inputs documented for design team agreement.
Overheating assessment report
TM59 or TM52 compliance documentation with hourly temperature results and pass/fail summary.
Thermal comfort analysis
PMV, PPD or adaptive comfort results for representative spaces and seasonal conditions.
Indoor air quality report
Ventilation effectiveness and CO₂ concentration analysis for occupied spaces.
Daylight analysis report
Daylight factor, UDI and glare assessment with facade optimisation recommendations.
Parametric facade study
Glazing, shading and insulation trade-off analysis with performance comparison.
Natural ventilation assessment
Airflow network modelling results with opening strategy recommendations.
Certification credit documentation
WELL, BREEAM or LEED IEQ credit evidence formatted for assessor submission.
Design recommendations report
Performance-driven recommendations for architectural and MEP design integration.
Post-occupancy evaluation report
Operational performance comparison with occupant feedback and improvement recommendations.
Monitoring specification
Sensor types, locations and data collection requirements for operational verification.
Performance visualisation
Colour-coded model outputs and hourly profile charts for design team presentations.
Quality control and verification
Simulation inputs independently reviewed against architectural and MEP design documentation.
Overheating criteria applied per current methodology version with climate file documented.
Comfort results cross-checked against manual calculation for representative spaces.
Post-occupancy data normalised for weather and occupancy before comparison with predictions.
Certification documentation verified against current credit requirement versions.
Design recommendations reviewed with architectural and MEP teams before report issue.
Applicable project types
Residential towers requiring TM59 overheating compliance for planning approval.
Naturally ventilated office buildings assessed against TM52 and adaptive comfort criteria.
Healthcare facilities with stringent IAQ and thermal comfort requirements.
Educational buildings with daylight, ventilation and overheating compliance needs.
Retrofit projects assessing improvement measures against operational performance baseline.
Certification-driven projects targeting WELL, BREEAM or LEED IEQ credits.
Frequently asked questions
What is the difference between TM59 and TM52 overheating assessment?
TM59 applies to residential buildings with bedroom and living room overheating hour limits. TM52 uses three criteria based on operative temperature for non-residential naturally ventilated and mixed-mode buildings. Selection depends on building type and planning requirements.
When should overheating analysis be conducted?
Overheating analysis should inform facade and ventilation design decisions at concept and schematic stages. Planning submissions typically require completed analysis before detailed design approval.
How is post-occupancy evaluation conducted?
Metered energy data, indoor environmental monitoring and occupant surveys are compared against design-stage predictions. Variance investigation identifies operational, commissioning or design factors contributing to performance gaps.
Can building performance analysis support WELL certification?
Air quality, thermal comfort, daylight and acoustic assessments provide evidence for WELL feature compliance. Analysis scope is aligned with specific WELL feature requirements at project outset.
How are natural ventilation strategies validated?
Airflow network modelling simulates wind and stack-driven ventilation through proposed openings. Results verify adequate ventilation rates and overheating compliance without mechanical cooling.
Discuss building performance scope
Contact our building performance team to review overheating assessment, thermal comfort analysis or post-occupancy evaluation for your project.