This publication highlights a path forward for the buildings sector to be much less energy and carbon intensive, while investing in high-performance buildings and highly efficient products. A large focus is piut upon improving technologies relating to the building envelope. The result reduces the need for additional and new sources of energy, with benefits for the environment and for energy security.
- More than 40% of the savings expected in heating and cooling energy demand under a low-carbon scenario can be directly attributed to improvements in the building envelope.
- Energy use is strongly linked to building age. There is large energy and Co2 saving potential in upgrading building envelopes and heating and cooling systems to modern standards.
- In OECD countries and non-OECD Europe and Eurasia, large-scale refurbishment of residential buildings should be the priority.
- Opportunities to integrate building end-use equipment into smart grids and smart metering should be promoted to help reduce peak load and bring other economic benefits.
Primary strategies and technologies needed for efficient buildings include high-performance envelopes optimised to harvest free solar energy and daylight, combined with advanced windows, optimal insulation and proper sealing, along with reflective surfaces in hot climates.
While it is hard to calculate, windows are most likely responsible for between five and ten percent of the total energy consumed in buildings within the Organisation of Economic Co-operation and Development countries (OECD). Shading attachments can be utilised in buildings where replacing windows is not possible. Insulated cellular shades (that look like honeycombs) can reduce u-values of the thermal envelope, therefore reducing heat loss through the window.
To make our buildings cool we can reduce solar heat gain through reflecting solar heat gains from the building. This can be achieved by installing external shading with highly reflective surfaces, e.g. when bright white shading is chosen, although this is less effective when low-e glazing is installed. Low-e coatings can also be applied to windows as films to reduce thermal loss and reflect thermal gain to make our buildings cool.
In addition, with better use of natural lighting and adoption of highly efficient lamp technologies energy consumption for lighting in buildings could be reduced by up to 40% by 2050 compared to current levels.
Currently, space heating and cooling together with water heating are estimated to account for nearly 60% of global energy consumption in buildings. In the EU most of the energy consumption by buildings is used for heating. Where a high-performance building envelope in a cold climate requires just 20% to 30% of the energy required to heat the current average building within OECD countries. In hot climates, the energy saving potential from reduced energy needs for cooling are estimated at between 10% and 40%.
A systems approach, where equipment upgrades are coordinated in particular with improved building envelopes, will be key to achieving higher energy efficiencies and a low-carbon heating and cooling supply. Research and development is required in envelope technologies such as cool roofs and advanced window shading to reduce costs. Enhancing the performance of products will lead to improvements in the efficiency of the building sector and reduce expected cooling and heating energy costs.
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