Cities substantially contribute to European air pollution as they are the source of about 36% of the total CO 2 emissions. Modern cities therefore raise sustainability concerns.

Those who live in low-energy buildings are not experts. But energy professionals have been aware of the importance of meeting their needs, right from conception stage.

Restoring historic buildings and saving energy at the same time is now a reality. Passive house window expert Franz Freundorfer developed the heat-saver for the Waaghaus in Bolzano, a building from the 13th century .

A well-accepted measure for climate protection involves reducing greenhouse gas emissions . And buildings have the greatest energy saving potential, according to the official EU Energy Efficiency Plan 2011 .

Historical buildings and town quarters are an integral part of the European cultural heritage. However, such buildings are often not very energy efficient and thus contribute substantially to the emission of greenhouse gases.

The construction of a building does not only start with its design by architects and engineers.

Ulrich Filippi Oberegger is a senior researcher in the energy management in buildings group of the Institute for Renewable Energy of EURAC Research . He tells youris.

The building sector has traditionally been fragmented. Many different actors are involved at different stages, from the design to the performance monitoring stage.

EnginSoft , is an Italian consultancy specialised in computer-aided-engineering. It has experience of contributing to the development of low energy buildings, under the EU-funded DIRECTION research project.

To make a building sustainable, taking into account its climatic conditions is key. No better examples than the three showcase buildings under the EU funded  DIRECTION project.

Sustainable buildings partly depend on control strategies to be energy efficient.

Carlos Bárcena, head of R&D Projects at the Spanish construction Company  DRAGADOS .

A new Directive, dubbed the energy performance of buildings Directive (EPBD), brings the new concept of net -zero energy buildings (NZEB) meaning buildings with a zero energy balance that have a better level of energy performance than the standard energy efficiency requirements in current building codes.

Going from modern energy efficient houses to historic buildings must have been a big leap for you.

Window refurbishments stand out as a viable approach to dramatically reduce energy loss. As their first case of study, the project’s researchers chose to upgrade the windows of the ‘Waaghaus’ (Public Weighing House), a building located in Bolzano, Italy, that is over seven-century-old.