Working file R1
Retrofit cost London (2026)
Retrofit cost London (2026): regional labour-rate premium, stock mix, regional scheme overlays, indicative deep-retrofit envelope.
Labour-rate premium
London labour rates run 15 to 30 percent above the national mean across the heating, fabric and ventilation trades. The mean ASHP install in London sits at around £14,500 vs the national £12,500.
Conservation overlay
A large share of inner-London stock is in a conservation area or carries an Article 4 direction. EWI is usually ruled out; IWI plus heritage-glazing is the standard route.
GLA Warmer Homes London
Warmer Homes London continues to operate as the LA-led overlay; means-tested route via local boroughs. Useful for the cohort that also qualifies for ECO4 / GBIS.
Surveyed 22 June 2026. Ofgem Q3 2026 cap applied (gas 7.33p, elec 26.11p, gas standing 29.04p). Next scheduled review 26 September 2026 (Q4 cap publication). [ref R1]
By Oliver Wakefield-Smith, Founder, Digital Signet. Corrections to oliver at digitalsignet dot com.