Designing a low-energy tall building with Daisy

As the UK and the wider world navigates grid constraints, heating and cooling can no longer be treated as an MEP problem to solve in isolation. It has to be designed in from the start. That means moving away from linear‑led design and towards passive, climate‑responsive, iterative approaches.

Key takeaways

Linear design processes risk embedding energy inefficiencies before their impact is fully understood

Each facade faces distinct solar conditions – uniform approaches leave significant performance gains unrealised

The greatest performance improvements come from testing design combinations early, when flexibility and cost-effectiveness are highest

An integrated approach across facade, MEP and smart building strategies delivered a 72% operational energy reduction with a six-year payback

United Kingdom | 17 June 2026
Reading Time : 5 min

We recently explored this opportunity for a client with a mixed-use tall building, located in a place that typically experiences a mediterranean climate year-round. Their ambition was to create a development that came as close as possible to achieving Net Zero Energy without changing the building’s shape. Using our Daisy tool, we showed the performance gains that can be achieved by rethinking how design decisions are tested and combined.

This article explores how we partnered with the project team to deliver a tall‑building study using our Daisy tool. By testing hundreds of design scenarios in parallel, we revealed how passive performance could be maximised through the right combination of interventions, protecting architectural intent while strengthening energy outcomes.

Why we must shift from a linear to iterative design approach

Looking at how building design is typically approached, this is usually a sequential design process that involves determining things in the following order:

Shape and massing (architecture)
Window-to-wall ratio (views and light)
Solar shading devices (passive measures)
Glazing performance (transparency and light)

After all these things are considered one after the other, MEP systems are then designed to support a comfortable internal environment. The problem with this approach is that you can’t easily understand how each factor impacts one another and the consequences of different design options.

This also limits the full potential of passive design measures in supporting energy efficiency and how different interventions can reduce heavy reliance on MEP systems. This also can result in over-designed systems that work harder than needed to support comfortable internal temperatures, a challenge that can be unlocked through iterative design.

Diego Padilla Philipps

Director, Decarbonisation and Innovation, Property and Buildings

United Kingdom

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What our study uncovered about designing energy efficient tall buildings

Our recent building energy study highlights how iterative design approaches can reshape the building design process, ensuring that the architectural ambition is protected and integrated effectively alongside building performance and client objectives.

The sun impacts each elevation differently

Solar irradiation, which is the amount of solar energy a building receives over time, directly affects internal temperatures, comfort levels and energy demand. During summer and winter, this can have different impacts on heating and cooling needs – and the path of the sun means that each side of a building will absorb sunlight differently.

Factors such as orientation, facade design, glazing ratios and shading determine how much heat a building absorbs or deflects, influencing everything from cooling loads to operational costs. This means buildings need different passive interventions for each elevation to adjust to unique sun-related conditions.

Better decisions need joined‑up data

To understand the consequences of different design options clearly, we built a specific parametric model to cover various aspects of the building, from different elevations to glass panels and shading devices (horizontal and vertical). We worked with each of the discipline teams spanning architecture, facades and building services to collect the building physics information to support this.

This meant we could create an integrated simulation that could assess how different nominal scenarios impacted one another together to maximise different passive design approaches in response to different sun-oriented scenarios.

Different elevations need different answers

Our parametric model assessed the consequences of applying different interventions across each of these factors. We looked at how adding more or less of one factor across each of the elevations could influence the building’s projected energy efficiency.

What our study showed was that south‑, east‑, west‑ and north‑facing facades cannot be treated uniformly – the optimal balance between shading and solar gain shifts by elevation and by use, and excessive shading can reduce cooling loads in summer while driving up heating demand in winter.

For example, we found that reducing the shading area by 40% on one elevation could optimise heating and cooling consumption in summer and winter. Effective energy performance depends on orientation‑specific shading strategies that respond to local sun paths rather than a one‑size‑fits‑all facade approach.

From analysis to buildable outcomes

Following our analysis and identification of potential solutions, we presented the nominal performance outcomes to facade, MEP and building performance teams – who reviewed and could propose specific buildable solutions to align with interventions. The smart building team could then look at the outputs and create a smart strategy that complemented this.

Our study showed that by analysing facade optimisations with MEP integration and smart systems in this way, this strategy delivered a 72% operational energy reduction and a six-year payback.

Every project is a multi-objective-optimisation problem

Traditional linear design processes have shaped many of the buildings we see in cities today, often resulting in facades that are treated uniformly, regardless of orientation or context. While this approach feels comfortable and like the simple solution, it can also lead to missed opportunities for passive performance and create inefficiencies that are increasingly difficult to change as projects progress to later phases.

As the built environment navigates a fast-evolving landscape shaped by economic, environmental, political, regulatory, social and technological factors, there is a growing need to rethink how design decisions are made to support adaptability. Daisy can support this shift by introducing a parametric, simulation‑led process at concept stage, allowing teams to explore multiple performance-oriented design combinations at once, while design flexibility is high and is more cost-effective to explore changes.

By grounding decisions in evidence rather than assumption, digital tools like Daisy help project teams uncover better‑balanced solutions – joining up expert insight across disciplines and giving greater confidence that design intent and performance outcomes can progress together.

Unlock potential with WSP’s Daisy tool

Combining advanced computational solutions with multidisciplinary design insights to help you explore optimal options for high-performing buildings at concept stage.

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