Pushing the envelope: improvements to buildings’ outer layer can slash energy use
18 December 2013
Buildings use more energy than any other sector and therefore are a prime focus of efforts to save energy. A new IEA publication shows how improvements to the building envelope – the parts of a building that form the primary thermal barrier between interior and exterior – can cut the sector’s total consumption by almost 20%.
Technology Roadmap: Energy Efficient Building Envelopes analyses emerging technologies that improve the envelope – which includes walls, windows, doors, the roof and floors – like high-performance “thin” insulation, triple-glazed low-e windows, dynamic solar control and better air sealing. Detailing the investment, policies, regulations and actions necessary to advance and popularise these technologies in new and existing structures, the new publication lays out a strategy for transforming how buildings are constructed or renovated. And it proposes long-term solutions to limit growth in the sector’s energy use, which currently includes more than half of global electricity, despite global population growth of 2.5 billion people by 2050.
For instance, improvements to the envelope could reduce total heating and cooling energy demand in 2050 by the equivalent of the United Kingdom’s current total consumption. For hot climates, the roadmap shows how low-cost solutions like reflective roofs and walls, exterior shades, and modern window coatings and films can cut energy use for cooling that otherwise is expected to increase by as much as 600% in emerging economies. Similarly, in cold climates, optimised building design and advanced window and glazing systems can improve passive heating. Overall, heating and cooling loads can be reduced typically by at least 40% through efficient envelope technologies.
That is just a start. Improving new construction is particularly important in emerging economies, where more than half of the buildings projected to be needed in 2050 are yet to be built. The roadmap describes the policies necessary to reduce the cost of zero-energy buildings and move niche technologies and products into the construction mainstream. In OECD countries, most current buildings will still be standing by 2050, so the roadmap provides a plan for incentivising deep renovations that can cut consumption by as much as 75%.
Technology Roadmap: Energy Efficient Building Envelopes follows two other IEA publications this year about energy efficiency in the buildings sector: Transition to Sustainable Buildings: Strategies and Opportunities to 2050, which demonstrates how to achieve deep energy and emissions reduction, and Policy Pathways: Modernising Building Energy Codes, which evaluates best practices in regulation for more efficient buildings.