Giffords energy efficient Carlton House, near Southampton

According to the BRE slightly less than half (44%) of UK carbon emissions are directly a result of our use of buildings¹.  This does not include transportation associated with buildings, which is counted separately.  

While housing represents the greatest segment of this, the financial issues are somewhat different to the commercial world and will be addressed in later articles.

In relation to commercial/office buildings, the OGC estimate that the ratio of construction costs (including fees etc) to running costs (including staffing) for a typical building will be of the order of 1:200 over a thirty year building life².  In many buildings energy usage will be significantly the greatest cost on a year-on-year basis for building owners/users – often of the order of 30% of the operating expenses of a facility.

When Giffords designed their new office, Carlton House, near Southampton, their aim was to develop a building form that would be highly energy efficient but fall within the cost norms for similar traditionally designed buildings.  At £128/sqft, the construction cost fell comfortably within the mid-range for a typical medium specification office building at the time it was constructed (2005).  

Where Carlton House differs from the norm is in its energy consumption.  By thinking carefully about the built form and the servicing strategy from the outline design stage Giffords have reduced actual electricity consumption to less than 25% of the CIBSE (Econ 19³) norm (just over a third compared to Econ 19 best practise for the time) and gas usage to 17% of the norm (31% of best practise).  Their actual measured total energy usage is only 20% of what would have been expected, with a corresponding reduction in CO₂ emissions.  Giffords have shown that you can take that 30% of the operating facility cost and reduce it by 80% by careful design.  This demonstrates that in a highly efficient building, an organisation can save between 20% and 25% of its operating outgoings – this has to be a significant saving for any business.

There is also evidence that commercial buildings with an ‘eco’ badge, i.e. buildings with low running costs, can demand higher rents than the norm, and that those rents have increased faster than is typical as well – even during the recession.  While it is recognised that low energy buildings often have a modest on-cost (increased capital cost) compared to the norm, this can be kept at the lower end of the range if the consideration of environmental performance is an issue from the very beginning of the design process, at demonstrated by Carlton House.  If this can be achieved the percentage increased rent levels should more than outweigh any additional construction cost, thereby making low energy buildings more profitable than their ordinary competitors. 

This starts to break into the vicious cycle of ‘do nothing’ that it is so easy to fall in to:  

The message that comes through very clearly is simply that good design which puts sustainable thinking at the core of the design process, makes sound economic sense, regardless of the extent to which a client, or indeed the architect, believes – or not – in the environmental consequences of development.  So sustainable design gives a financial ‘win’ for clients and building users and a USP ‘win’ for designers.

And the good news is…if the climate change scientists are right, any savings in energy costs equate directly to reductions in CO₂ output, so we have a ‘win’ all round.

This article is the first in a series exploring the principles of sustainable design, the available technologies and related matters of interest.  The next will consider general approaches to sustainable design and after that we will be looking at specific strategies that can be followed.

References/further reading:

1. www.naturalchoices.co.uk/Who-pays-for-Green-Economics-of?id_mot=1

2. www.ogc.gov.uk/documents/CP0067AEGuide7.pdf 

3. www.cibse.org/pdfs/ECG019.pdf 

Verity Bird

Verity Bird has been a Senior Lecturer in Architecture and Interior Design at Southampton Solent University with a particular interest in sustainability for the past four years. The bulk of her career, after several years in private practice in the 1980s, was with city of Bradford’s Architects department where she rose from project architect to group leader level.  Verity has been interested in environmental issues for many years and was involved in the Agenda 21 group in Bradford, speaking at local conferences into sustainability and energy use minimisation during the 1990s.  After leaving Bradford she worked in the Estates and Facilities service of Southampton University for a short period before moving into academia at Solent.