Constructing and using buildings is responsible for around one third of UK’s current carbon emissions, so if we are serious about keeping global warming within 1.5 or 2°C then buildings must be designed to much higher energy standards – such as UK’s Code for Sustainable Homes level 6 or Germany’s Passivhaus rating. However in 2015 the government abolished the statutory requirement to build to these energy standards.
Current new builds tend to involve a higher amount of factory prefabrication, largely aiming to reduce costs and construction times – although the higher precision of construction and optimised material use can also improve heat loss performance. Designs often do pay greater attention to heat loss, minimising this by adding more foam or fibre insulation to masonry walls or else using prefabricated timber frameworks and (in principle) minimising draughts and air leaks. Masonry and industrial insulation products both use large amounts of energy to produce, so this ’embodied energy’ in construction is still not well addressed – but wood frame construction can have a better environmental footprint if the timber is responsibly sourced. So the general UK picture is of more optimised industrial technology giving some improvements in sustainability for new builds – but very little is being done to address the much greater issue of energy performance in UK’s ‘legacy stock’ of buildings already constructed. A small minority of construction, however uses ‘natural building’ methods, which take a very different approach to provide good sustainability in both construction and long-term use.