Alice Ross asks: Which path to take to greener buildings in our cities?

1. Live compact
Our crowded planet doesn’t have the space or resources for endless, sprawling suburbs. “Vast, spread-out houses aren’t sustainable. They burn through heating and electricity,” says Nick Hancock. “We also need cities that are more compact so that fewer people require cars to get around. We need density.” Designing for denser urban textures pushes architects to use every inch of space creatively, particularly for homes:“ People don’t want to live in crappy little boxes, and why should they? We have to design homes that are compact but practical, that are efficient to run, and that change with people’s needs.”

2. Build for keeps
In the past few decades, buildings were often built to stand for just 20 or 30 years. By that time, the reasoning went, trends would have moved on, requirements would change, and it’d be time to knock the building down and start again. This won’t do any more: “Demolishing a building takes a huge amount of energy, and putting up a new one takes more-plus the embodied energy of all the materials and their transportation,” says Hancock. “We have to think about longevity, about choosing materials that will age well.”

3. Reuse and recycle
The flip side of this is finding ways to reuse existing spaces: taking the dingy, draughty buildings of previous ages and making them more pleasant to be in, and greener. “You can completely transform a building while keeping basically the same structure,” says Hancock. He reels off measures: insulation, draught seals and Argon-filled double glazing to prevent heat loss ; lightwells, glass floors and skylights to flood spaces with natural light ; and new facades with sun shading and natural ventilation.“ Even something simple like windows that can be opened reduces the need for air-con. It doesn’t have to be super high-tech. Green thinking is just as important as fancy gadgets.”

4. Listen to the site
Architects never start from a blank slate; every building stands in a landscape. Harnessing this is key. “There’s free energy in the wind and the sun. The first thing you do is look at how your building fits within those parameters, how it makes the most efficient use of energy for that setting,” says Hancock. This can be as simple as orientation. “The sun rises and sets in the same positions every day. It’s the most efficient source of energy we have. But we have to manage this, using natural breezes and shading to prevent overheating. It’s about understanding what the context is before you start to solve the problem.”

5. Embrace the future
Green building doesn’t have to be particularly high-tech, but designers also have more sophisticated sustainable technologies at their fingertips than ever before. “Solar panels used to be a luxury; these days they’re cheaper and efficient enough to make a real difference.” All sorts of other systems are now within reach too: such as grey water systems which recycle tap water for other domestic uses, ground-source heat pumps which use thermal energy, and specially coated UV-resistant glazing. “My personal favourite is the green roof. It’s basically a sedum grass lawn on top of a building,” says Hancock. “It absorbs water, insulates your house and boosts biodiversity-it’s just clever.”

This and more inspiring projects can be found in A smart guide to Utopia.