Building Optimisation

Making the balance between design options visible

Reducing glazing, increasing insulation or selecting a different system can produce different energy and comfort outcomes in the same building. Building optimisation compares these options together against defined objectives. AECO analyses what each change affects and how objectives interact, helping the design team make a technically informed choice.

Work can begin in early design before details are fixed or focus on specific decisions in a developed design. Improvement alternatives for an existing building can also be assessed. The first step is to define the question: developing a façade, comparing systems or assessing energy and indoor environmental objectives together calls for different analytical arrangements.

We first establish which design features can change, their option ranges and the assumptions to be held constant. Orientation, glazing properties, glazing ratio, insulation, shading, lighting controls and mechanical systems can all be considered. Inputs such as schedules and climate enable options to be compared on a common basis.

Assessment criteria are also clarified at the outset. Where energy demand, cost or comfort objectives need to be considered together, multi-objective optimisation methods can be used. Calculated metrics are presented alongside their methods and assessment conditions.

Each result is connected with the input record for its option. The team can therefore trace a point on a chart to the glazing, shading or system decisions it represents. Graphics and comparison tables make results readable in relation to the assessment question.

Where multiple objectives apply, options in which improving one objective requires a trade-off in another become important. The Pareto front helps distinguish solutions illustrating that balance among the options assessed. The final choice considers performance results, feasibility and the client's priorities together.

When interpreting results, we explain the effects of variables and differences between options with similar performance. The team can consider practical alternatives alongside their technical rationale.

Where energy assessment is used for certification, comparison rules are connected with the relevant system and version. For example, a study following ASHRAE 90.1 Appendix G establishes its baseline using the rules of that method. The performance-based comparison framework is an official technical reference for this distinction.

Deliverables include variable and assumption records, comparisons of calculated options, graphics and findings relevant to the decision, and design recommendations. Results are reported alongside the options assessed. Separate sets of analyses are interpreted against their own starting conditions.

For the relationship between energy calculations and building decisions, see our energy modelling service; for an introduction to the approach, see our parametric analysis and optimisation article.