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ESB Offices – Fitzwilliam Street


Location Client Cost Size Completion
Fitzwilliam Street Lower, Dublin, Ireland ESB €150m 45,000 sqm 2022

Project details

This is a set of two new office buildings within a single city block. 

The ESB’s offices are an exemplar of sustainable design, offering a treasure trove of new design techniques for the next generation of low energy offices.  The second office is a commercial implementation of many of the new techniques used within the ESB’s offices and provides the market with a real alternative the traditional, sealed office.

The buildings use a new form of hybrid ventilation that takes advantage of the exceptional natural cooling potential available in Ireland while providing an office space with an environmental space quality that exceeds that of traditional ventilation options.

The buildings contain an abundance of new passive and active sustainable design techniques, many of which are completely innovative and new to the office market.

The design team took a personal interest in the project and worked diligently to ensure that a unique building was achieved that is likely to stand as precedent sustainable design for many years


BDP embraced the offices as a research project that reimagines every traditional system within an office and produces new techniques that enhance energy performance, space comfort and quality. BDP are currently monitoring and tuning the building and results will be published on completion of the monitoring period.

The building contains new techniques in the following areas:

  • Hybrid ventilation and free cooling, reduce active cooling close to zero
  • New fresh air delivery techniques result in approximately 85% less fan energy
  • New air delivery techniques for meeting rooms reduce energy usage dramatically
  • Single coil fan coils reduce fan and embodied energy
  • Heating energy usage approaches zero and is provided almost entirely from recovered heat
  • 100% of domestic hot water is provided from recovered heat
  • Free cooling is provided from a ground loop system
  • Advanced phase change material stores free cooling potential
  • A glycol free cooling system reduces waste and improves efficiency
  • Demand controlled kitchen ventilation with heat recovery is used
  • A plethora of new energy and comfort control techniques are used
  • Air quality is enhanced and monitored by active VOC meters

In addition to the new methods used, the building is a zero pollution, zero fossil fuel building that includes best practice techniques in water conservation and biodiversity. The building is also BREEAM Excellent certified for its approach to holistic sustainability.

The research work has resulted in significant insights into the design of future office buildings and our engineers have already implemented further refinements of the techniques within our future projects.


  • provide a set of office buildings with an environmental performance that exceeds that of any similar scale office in Ireland, setting a precedent for future office design


  • playing an active role in the development of building layout and facades to optimise its passive response
  • development of a range of active and renewable energy and water systems for the building
  • irish Building and Design Awards 2022 - Irish Building Project of the Year award
  • irish Construction Industry Awards 2022 - Large Commercial Project of the Year

Integrated services

environmental engineering, sustainability, lighting, BREEAM Accredited Professional

For more information contact