What colour is your building? (David Clark)

electrical consumption, energy efficiency, green building, housing, renovation

Measuring and controlling energy consumption in sustainable buildings

In his book What colour is your building?, David Clark looks into energy consumption in office buildings and provides measuring tools as well as ways of minimizing wastage. He suggests practical solutions to improve energy efficiency and energy consumption management in the built environment, in a bid to reduce harmful CO2 emissions. This poses a significant challenge to businesses, building occupants, construction managers, designers and architects.

Buildings (tertiary and residential) account for 40%[i] of overall energy consumption and 30% of greenhouse gas emissions (the latter rate is expected to double in 20 years). The author thinks that it is possible to build zero-emission buildings without major upheavals. Today, clean buildings do not yet exist: in 2013, the lowest emission rate was 30 kg CO2/m2.

Measuring buildings’ carbon footprint to increase energy performance

Improving energy efficiency in buildings is not only about using higher performance materials (such as mineral wool for insulation) at the construction stage; office occupants must also change their ways of using energy.

In order to curb energy consumption, David Clark provides a method to carry out a 10-step energy audit[ii]. First, the amount of energy consumed in a given building must be measured and a limit must be set. The next 6 steps help identify various uses and assess their respective carbon footprints: lighting, ventilation, appliances (computers…), etc. Finally, Clark emphasizes the importance of behavioural patterns and smart office maintenance, as office occupants must be involved for energy to be effectively saved[iii].

Clark’s book provides practical comparative tools for a global approach to measuring buildings’ carbon footprint. Assessing the emissions of a given building requires various data, including construction details, surface area, carbon emissions per person … Polluting emissions rates should then be made public on a yearly basis, in order to encourage office managers and occupants to redouble their efforts.

Less energy-intensive and more intuitive technologies can improve buildings’ energy performance. Some companies already rely on occupancy sensors and heat-recovery (dual flow) ventilation to save energy. Constructors, architects and designers must also be involved in the process, as buildings must be designed, constructed or renovated in a clean, smart way. So-called passive design plays a crucial role in this respect; “passive solar design”, for instance, aims at optimizing exposure to daylight (e.g. by use of tiltable windows).

Comprehensive and local approach

In order to assess office buildings’ overall carbon footprint, David Clark proposes to resort to a tool know as whole carbon footprint benchmarking. It takes into account the overall energy consumption that is indirectly related to office buildings, for instance that of the factories which produce materials used for construction and equipment.

Clark places a particular focus on the means of transportation used by building occupants to reach the workplace; in the UK, transports account for 20 to 25% of overall CO2 emissions, the favourite means of transportation being cars (78% in 2011). The author therefore suggests that the location of office buildings should minimize car use and encourage reliance on public transportation. The use of clean transportation is indeed instrumental in reducing buildings’ overall footprint. This comprehensive approach shows that the rate of public transportation use is higher in cities, especially in London (48% increase in 2011)[iv].

This approach also includes energy generation and supply. According to the author, self-generation is the best option, i.e. installing renewable energy sources (such as photovoltaic) within buildings for electricity and heating. However, as every building has distinct features (location, technical possibilities), tailor-made solutions are in order. The use of biomass, for instance, may not be ideal everywhere due to supply and storage problems.

Clark concludes by putting this paradigm shift in perspective, arguing that while it has an environmental dimension, it must also become an economic issue: investments must be made in this new clean building sector. This also matters for office occupants, who can cut production costs by curbing energy consumption, thus making their business more competitive. For Clark, it is now time people changed the colour of their buildings.

[i] All statistics in this piece are drawn from What is the colour of your building?

[ii] Cf ADEME (French agency for the environment and energy management) proposals for business energy audits ; see also ADEME Centre- Val de Loire

[iii] ADEME Centre- Val de Loire supports the creation of “energy contact persons” positions

[iv] For more information, see Appendix  F to Clark’s work

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