Thirty-one apartment buildings comprising 140,000 m 2 of floor space: Europe’s most ambitious energy-saving renovation project is transforming Torrelago, a residential district of Valladolid in central Spain.

Spain is known as a land of sun and heat. But even here there are regions that have to face icy winter temperatures. In Valladolid , in the north of the country, many of the almost 300,000 inhabitants are in poorly isolated buildings built in the 1960s.

From 21 to 25  May the EU Green Week is exploring ways to accelerate sustainable urban transformation.

Bristol is at the forefront of high-tech innovation in the UK, named European green capital in 2015. But it is also the second least affordable major British city housing-wise only after London.

When temperatures are low, the temptation to take long, scalding showers and turn electric heaters to the maximum is high. And not knowing how much energy we spend, when we unthinkingly do these activities, makes it difficult for us to decrease our consumption.

From the frosty reaches of Umeå in eastern Sweden to the rolling hills of San Sebastian in Spain’s Basque Country, European cities have one refrain on their minds as the cold sets in: winter is coming and homes must be heated in a way that allows the EU to reach its goal of reducing energy consumption by 20% by the year 2020 .

Energy consumption in the construction sector is a key issue in the fight against climate change. It is often approached when planning new buildings, but there is little tendency to renovate the existing stock .

Smart buildings appear to respond to a range of energy challenges found in Europe today. Improved efficiency would help consumers reduce income spent on energy consumption, reduce greenhouse emissions and also help EU countries meet the goals of the 2030 energy strategy .

Buildings account for 36% of CO 2 emissions in Europe, and energy consumption in this sector has increased in recent decades.

Today, one of the new challenges for the construction industry is the use of textiles, coming from the clothing and footwear industries.

Suburbs are often spaces of poverty, unemployment and urban decay. But now many peripheral areas are becoming laboratories of innovation , hosting initiatives for a sustainable future.

The European construction industry and home-builder citizens are increasingly aware of sustainable choices. Some solutions can be more expensive than others, although sometimes this only concerns the construction phase.

Cooling and heating public buildings remains an expensive and a mostly unresolved issue in Europe. According to the not-for-profit think-tank Buildings Performance Institute Europe , Spain has about 11.

“The building sector is responsible for more than 30% of global energy demand and round about 20% of greenhouse gas emissions”, says Peter Graham from the Global Buildings Performance Network in Paris.

In Europe, households are responsible for 32% of greenhouse gas emissions and 42% of energy. Cement production alone contributes to 5% of manmade CO 2 emissions .

The worldwide energy consumption of buildings is expected to grow by 45% from 2002 to 2025, according to the SMART 2020 study carried out by the international NGO The Climate Group.

The Cuarto de Marzo district of Valladolid, Spain , is an area spreading over 21,000 square metres with 166 residences. It is now the focus of a retrofitting project , called  R2CITIES , funded by the EU.

These weather conditions are a challenge to construct a smart building that can save energy throughout the year.

To tackle climate change, new buildings are required to consume as little energy as possible . That’s because, in Europe, buildings are responsible for about 40% of our energy consumption.

In a strategic plan for the municipality, the town council of Valladolid , in Spain, has given top priority to the renovation of its heritage buildings to achieve nearly zero energy districts.