Houses need to be a lot more energy efficient than most of them are right now. Knocking down every house and block of flats which doesn't meet rigorous standards and building from scratch would do it. But that's a pipedream.

Firstly: it's totally impossible. People are living in those buildings, and most of them couldn't afford it.

Secondly: it's doubtful there would be enough resources. It would take vast amounts of wood, cement, bricks – and would generate mind-blowing amounts of waste.

So, we must face facts: if we can't build new, we need to renovate. As efficiently as possible.

The Horizon 2020 e-SAFE project is trying to change the way we approach building retrofitting, with an emphasis on circularity and waste reduction. It combines energy efficiency, seismic resistance, financial feasibility and various social benefits.

e-SAFE's approach is rooted in curbing material consumption and avoiding demolition by promoting circular use and life extension of buildings and embracing a business model that minimises waste and maximises the longevity of existing structures.

The project opts for technical solutions with a low environmental impact: one example is outer wall panels made of a timber structure combined with local insulating bio-materials and the desired finishing. Bringing existing buildings up to spec is a lot more efficient and generates vastly much less waste than building new ones!