Creating a new office for the Environment Agency demanded a building with sustainability at its heart — from construction to operation. In response, Arup designed Horizon House, the UK’s highest BREEAM-rated office building when it opened. It went to win the 2010 BREEAM Award for offices. (BREEAM is a widely adopted environmental assessment method for buildings).
Optimising for environmental excellence
Working closely with the developer and contractors, the design team set out to go beyond the BREEAM ‘excellent’ score of 70% by greatly improving the environmental performance of the building.
Energy use is minimised through a mixed mode ventilation system; effective natural ventilation of the deep plan office is achieved by strategic building design. The building uses ground source heat pumps, solar water heating and photovoltaic panels as renewable energy sources.
Rainwater is collected from the building’s roof and used to flush toilets. The post tensioned floor slab provides lower environmental impact over the whole life of the building.
The primary source of cooling is the ground source heat pumps. Hot water is provided by solar panels and is supplemented by the ground source heat pumps and gas boilers. Photovoltaic panels supplement the mains electricity
A lighting control system detects whether the offices are occupied and dims the lights during the day.
These measures ensured Horizon House scored particularly highly for its contribution to the well-being of occupants compared with other excellent-rated buildings.
The focus on sustainability continued throughout construction. Arup’s design reused materials to minimise the environmental impact of the build. It specified that demolished concrete from the site should be crushed and graded, then used again in the new building’s sub-base.
Contractors monitored the carbon, energy and water impact of construction, and used timber certified under ISO guidelines. They also tracked recycling rates, along with the destination of demolition and site waste.
This project combined effective strategic planning with a commitment to sustainability from everyone involved. As a result, Horizon House achieved an unprecedented BREEAM score of 85.06%.
Horizon House shows the sustainability performance that can be achieved with excellent strategic planning and design.