Public administration bodies often own or occupy a considerable number of old or new buildings that can be intended for various uses, such as offices, schools, hospitals and warehouses, depending on each municipality’s competencies. Buildings are a key area of action as they are responsible for nearly 40 per cent of final energy consumption (and 36 per cent of greenhouse gas emissions) and they provide the second-largest untapped and cost-effective potential for energy savings after the energy sector itself (EC, 2013c).
Maximising the energy efficiency of public buildings and minimising their energy use can be achieved by improving the energy performance and integrity of the building envelope and increasing the airtightness, as well as installing energy-efficient equipment and commissioning energy systems.
Examples of retrofitting techniques are:
- changing insulation materials, increasing insulation thickness and improving environmental performance of the roofs
- using more efficient glazing sashes and frames
- using internal and external shading devices
- improving airtightness by improving doors, adding fast-acting doors, sealing air leakages and creating buffer sections
Both new and existing public buildings can be retrofitted and achieve better energy performance by complying with more demanding standards (such as the Passive House, Minergie or Minergie-P) than the minimum set out in the national building codes, becoming net-zero energy buildings ahead of the EU obligation.
When defining the measures to improve the energy efficiency of a building, it is necessary to consider the overall environmental impacts over the whole life cycle of the building, not just the energy performance target. This approach will lead to a more holistic view of the building and will involve actions like selecting sustainable and low-embodied primary energy construction materials. This will ensure, at the design phase, that the building will be easy to adapt to support any future reuse and easy renovation (for example, flexible floor plans). It will also support easy deconstruction for reuse and recycling of building materials and elements.