Building emissions go beyond electricity and heating. Embodied carbon — the emissions from making materials like concrete, steel, glass, and aluminum — accounts for roughly 11% of global greenhouse gas emissions. Concrete alone causes about 8% of global CO2, making it one of the most carbon-intensive materials on Earth.

Cleaner options are emerging: low-carbon concrete, recycled steel that needs far less energy, and bamboo as a renewable structural material. The greenest building is the one that counts its construction emissions, not just its running costs.