Tom Johnson House

Tom Johnson House, originally constructed in the 1970s, underwent a comprehensive deep retrofit to meet modern energy and environmental performance standards. Delivered under the OPW’s Public Sector Retrofit Pathfinder Programme, the project demonstrates how existing public buildings can be successfully transformed to support Ireland’s climate goals and futureproof government infrastructure.

The works included a complete upgrade of the building’s thermal envelope, mechanical and electrical systems, and internal configuration. These interventions improved the Building Energy Rating (BER) from G to A2, resulting in an 85% reduction in annual energy consumption and significantly extending the building’s operational life.

A key element of the retrofit was the decision to retain and repurpose the original structural frame and brick façade. This approach preserved embodied carbon and avoided the environmental impact of demolition and rebuild. Alongside this conservation strategy, the retrofit introduced high-efficiency technologies and reimagined the building’s internal layout to better support modern workplace needs.

The interior was transformed from traditional cellular offices into a flexible open-plan environment, allowing for increased occupancy and improved spatial efficiency. A central atrium was introduced to maximise natural light and ventilation, enhancing indoor environmental quality. Low-carbon heating and cooling are provided by advanced heat pump systems, aligned with the OPW’s Green Procurement Policy. The project also adhered to EU regulations governing sustainable construction, including responsible material sourcing, waste management, and circular economy principles.

Now serving as the headquarters for the Department of the Environment, Climate and Communications (DECC), Tom Johnson House stands as a benchmark in sustainable public building retrofit. The project delivers high energy performance, extended asset lifespan, and reduced carbon impact, while retaining the architectural character of the original structure. It exemplifies best practice in deep retrofit and showcases the public sector’s leadership in climate-responsive building transformation.