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Towards a green economy


building for which new materials and components were used. The results showed that the environmental impacts caused by reused materials are at 55 per cent of the impact caused if all materials had been new (Thormark 2000 and 2006). Other studies show that by using recycled materials between 12 per cent and 40 per cent of the energy used for material production could be saved. Reasons for the mixed results between studies include differences in recycling rates and the material composition in buildings.


Although recycling building materials requires energy consumption, studies show that recycling materials still delivers net emissions savings. Following a life- cycle approach (Sára 2001), compared CO2


emissions


from produced recycled clay/gravel with and without selective dismantling and classification. The research indicates that CO2


emissions were reduced from 107.7


kg to 6 kg per tonne of recycled clay/gravel produced. Recycling rates of specific materials that are significant in construction and demolition waste streams can be significant indicators of sustainability. In developing societies, recycled building components are often cheaper and of higher quality than conventional materials, providing benefits to the urban poor (UNEP SBCI 2010a).


Productivity and health benefits Green buildings provide benefits beyond environmental advantages at a low or negative cost. These include improved worker productivity and work quality resulting from a more comfortable office environment as well as improved public health resulting from reduced indoor air pollution (after replacing biomass with electricity or clean burn biomass in developing countries), reduced noise pollution and reduced overall air pollution (owing to reduced use of fossil fuels in developed countries and emerging markets).


These benefits can rival, if not supersede, the energy cost and climate benefits outlined above. For example, a recent study for the US Green Building Council estimated that greening an average US commercial office building saves US$ 5.6 per square metre per year in energy costs (Booz Allen Hamilton 2009).19


While significant in


absolute terms, energy costs for most businesses pale in comparison to labour costs, particularly in developed countries. Even a 1 per cent increase in productivity resulting from investment in green buildings yields a labour-cost saving several times higher than the energy-cost savings noted above. Results from a series of research studies on the effects of environmental conditions within workplaces show that productivity savings can be significantly greater than 1 per cent:


19. Original text indicates saving of US$ 0.52 per square foot per year in energy costs.


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Increased day lighting, views and contact with nature have also been linked to positive health and productivity impacts beyond commercial workplaces, for example, in hospitals and schools. Enhanced environments within school buildings are linked to improved student performance (Aumann et al. 2004) and those in hospitals have been associated with faster patient recovery (Ulrich 1984). Of 13 studies linking improved access to the natural environment with gains in individual and organisational productivity, seven identified 3-18 per cent increases in individual productivity (including student test results) and 40 per cent increases in sales (an organisational productivity measure) as a result of the introduction of daylight to workplaces (Loftness et al. 2003).


One of the earliest and most widely-cited studies on economies from green buildings documented 33 commercial buildings with green certification in California (Kats 2003). The report found an average green-building cost premium of US$ 32.3-53.8 per square metre.20


The total benefits of the investment


are highlighted in Table 4, which measured net- present value (NPV) over a 20-year period, showing net benefits of between US$ 516.7-721.2 per square metre, depending on level of certification.21


In developing countries, the health benefits of investment in the green buildings, specifically in technologies and appliances for heating and cooking, are directly contributing to improved human well-being. Indoor pollution is a major cause of serious illness and premature death in developing countries. Greening the building sector, in this context, is expected to derive its main benefits from reducing indoor pollution and improving the health of the poor, particularly women and children. Studies conducted by Ezzati and Kammen (2002) showed that the cost-effectiveness of measures


20. Original text indicates an average green-building cost premium of US$ 3-5 per square foot.


21. Original text indicates net benefits of between US$ 48-67 per square foot.


■ Indoor air quality: 6-9 per cent productivity gain (Wyon 2004);


■ Natural ventilation: 3-18 per cent productivity gain (NSF/IUCRC 2004);


■ Local thermal control: 3.5-37 per cent productivity gain (Loftness et al. 2003);


■ Daylighting: 3-40 per cent productivity and sales gain (Loftness et al. 2003); and


■ Rent premium: up to a 36 per cent increase (Baker et al. 2008).


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