Passivhaus profit

17 February 2012

The UK’s first carbon neutral PassivHaus office at the Watermead Business Park in Leicester

An office in Leicester which recently became the first carbon neutral building of its kind in the UK is allowing its tenants to generate £2300 in energy profit per year.

The recent installation of photovoltaic panels on the roof of the new regional office of Interserve Project Services, at Raynsway Properties’ Watermead Business Park in Syston, now means the 6000 sq ft building is the first carbon neutral PassivHaus office in the country.

As the electricity these generate exceeds the energy required by Interserve, the remaining power can be sold back to the grid, thereby generating an approximate annual energy profit of £2300.

The £1.5m two-storey building uses only about a tenth of the energy used in a conventional, non-PassivHaus building constructed to best practice standards. Excellent insulation, triple glazing and high levels of air tightness have all reduced the requirements for space heating and cooling, thereby providing high-level comfort with very low energy consumption.

Ashley Cowdrey from environmental building services firm CPW commented: “The installation of the photovoltaic panels at the Interserve building has resulted in even higher efficiencies than first thought, with an energy performance rating of -2 / A+. This means that the office is actually carbon negative in terms of regulated energy. The carbon saved by the electricity the building generates is greater than the carbon needed to run it. In effect it’s like a big man-made habitable tree.”

Tom Watkinson from developer Raynsway Properties, which owns and manages the business park, commented: “The fact that this office was amongst the first in the country to be built using PassivHaus standards was eye-catching enough but to now be the first carbon neutral office of its kind in the entire country really is a coup for Watermead Business Park and Leicester too. The finished building has caught the attention of businesses and environmental experts alike whilst leading the way in the future development of commercial property nationwide.”

The design of the new Interserve office used principles of PassivHaus, a well established German based building standard which reduces energy costs by approximately 90%. It saw the majority of work areas located on the highly glazed south side of the two-storey building to maximise heating in the winter, whilst blinds minimise the solar gain as required in the warm summer.

Its other environmental credentials include triple-glazed windows, roof lights and a zinc roof made of a high proportion of recycled material, which requires minimal maintenance. A ground-air heat exchanger exploits the natural heat energy stored in the ground and is able to draw air through an underground network of pipes, providing a source of both heating and cooling for the building.

Watermead Business Park is the only large, premium quality office development on the north side of Leicester. The 63-acre site is ideally located, fronting the A607 at its junction with the A46, overlooking Watermead Country Park.