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Embodied carbon is the carbon emitted making and building a home — the concrete, steel, brick, insulation and the construction itself (life-cycle stages A1–A5). London’s planning evidence puts business-as-usual upfront carbon for a new home under 11 m tall at about 500 kg CO₂e per m² — the same figure LETI set as its 2020 target for residential buildings. LETI’s 2030 target is under 300, and its baseline for a typical block of flats is about 800. A 100 m² house at 500 kg CO₂e per m² is on the order of 50 tonnes — around 2,273 tree-years, locked in on day one.
Unlike energy in use, you can't retrofit embodied carbon away — it's decided by design choices made early, so it's worth weighing up before the design is fixed. On the energy side of a new home, we produce the SAP calculations Building Control asks for and the energy statements planners ask for.
Source: GLA, Towards a New London Plan: evidence base for embodied and whole life carbon policies (Sept 2025) — homes under 11 m; LETI Climate Emergency Design Guide (2020). Figures are illustrative UK equivalents.
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Frequently asked questions
Is 500 kg/m² fixed?
No — it’s a benchmark for typical construction. Real figures depend on the structure, materials and design: a low-carbon specification can come in at 300–400 kg/m² or less, and a typical block of flats is nearer 800. For a defensible project number you need a whole-life carbon assessment.