##  [Building Performance Simulation](/building-performance-simulation-0) 

 Definition

The use of computational models and numerical methods to predict and analyse a building’s performance metrics—such as energy consumption, thermal comfort, daylighting, moisture transport and acoustics—over time, based on explicit assumptions about geometry, materials, systems, occupancy and climate.

 

 

 

 

 

 





## Principle

Principle

Simulation outputs are conditional predictions that depend on model fidelity, input data and scenario definitions; useful simulation supports comparative decision‑making and sensitivity analysis rather than serving as a single definitive forecast.

 

 

 

 

 





## Demonstration

Demonstration

Situation: A design team must select among HVAC systems. Recognition: Energy use, peak loads and thermal comfort implications differ between options. Action: The team builds thermal models for each system with identical occupancy and weather inputs, runs annual simulations and conducts sensitivity checks on occupant schedules. Consequence: Comparative outputs identify which system reduces projected annual energy and peak cooling while maintaining comfort across defined scenarios, informing selection and sizing.

 

 

 

 

## Misapplication

Misapplication

Treating a single simulation run as proof of future performance. The semantic error is conflating a model output under specific assumptions with guaranteed real‑world result; ignoring sensitivity, calibration, commissioning and occupant behaviour undermines reliability.

 

 

 

 

 





## Consequence

Consequence

Appropriately used, simulation enables exploration of design trade‑offs, optimisation of systems and evidence for compliance; misused, it can produce misleading confidence, result in undersized equipment, unexpected operational costs or failure to meet comfort and regulatory targets.

 

 

 

 

## Reversal

Reversal

When input data are very uncertain (early conceptual stage) or when regulatory prescriptive rules mandate a specific solution regardless of simulated performance, detailed simulation may be low value; conversely, in performance‑based procurement, simulation is essential. Also occupant behaviour and commissioning can dominate actual outcomes irrespective of modelling accuracy.

 

 

 

 

 





## Boundary

Boundary

Clearly within: dynamic thermal simulation with hourly weather data, detailed fabric and HVAC representations for annual energy and comfort assessment. Boundary case: simplified steady‑state or compliance check tools that approximate performance for code compliance. Clearly outside: back‑of‑envelope rules of thumb or visual appraisal without computational modelling.

 

 

 

 

 





## Semantic Tension

Semantic Tension

Model Fidelity ↔ Practical Timeliness and Interpretability — higher fidelity models can increase confidence but demand more resources and expert interpretation; project schedules and decision stages may limit permissible model complexity.

 

 

 

 

 





## Synthesis

Synthesis

Building performance simulation is a scenario‑based reasoning tool: its value lies not in single numeric outputs but in structured comparison, explicit assumptions and sensitivity testing that together make design trade‑offs and risks visible and manageable.