Green premium in SM4
Energy-efficient houses here sell for -3.6% per m² less than inefficient houses — age-adjusted across 1,074 sales.
In SM4, EPC-rated A-C houses sold for a median £6,099/m² against £6,329/m² for D-G-rated houses — a difference of -3.6% per square metre, comparing only homes built in the same construction era (3 era bands with enough sales on both sides). Figures cover HM Land Registry sales in the last 5 years matched to EPC certificates by address.
Why age-adjusted, not raw
A city-wide comparison of every efficient sale against every inefficient one is misleading on its own: older homes carry their own price premium or discount that has nothing to do with energy efficiency, and EPC ratings correlate strongly with build era. A Victorian terrace rated D can still out-price a 2005-built terrace rated B, simply because of where and when it was built — not because being less efficient made it more valuable.
Flats in SM4
The same comparison for flats specifically.
How this compares to national projections
A national dataset published July 2026 models a uniform England-wide retrofit premium of +5.8% (medium retrofit) to +10.9% (predicted retrofit) by 2050 — Panakaduwa, Figshare 2026 (CC BY 4.0). That figure is a single projection assumption applied equally to every English dwelling type — not a measurement, and not specific to SM4. The -3.6% above is what SM4 buyers actually paid, today, and — like most outcodes we've measured — it doesn't match the national assumption. The premium varies by area and by construction era in ways a single national number can't capture.
More on SM4
Buying a specific property in SM4?
This page covers the outcode as a whole. A free Property Report gets you the actual EPC certificate, energy costs and sale history for one specific address.
Sources: HM Land Registry Price Paid · MHCLG EPC Register · Open Government Licence v3.0. Reliable from 20+ sales per band, last 5 years.