21a, Mount Ephraim Lane, Lambeth, London, SW16 1JF

21a is a two-bedroom detached house in Lambeth, London, London (SW16 1JF). It has a recorded floor area of 93 m² (around 1001 sq ft), construction records dating it to before 1900 and council tax band C. The latest certificate (November 2025) shows an E (score 53), well below the UK norm with real room to improve. When first surveyed in August 2015 the rating was F, the property has climbed 1 band since. Between certificates, hot-water efficiency went from Average to Good, lighting went from Average to Good and main heating went from Poor to Good; while wall efficiency dropped from Average to Very Poor and window efficiency dropped from Good to Poor. The recommended improvements would lift it to C (score 71), a 2-band jump. At 93 m² this is the 5th smallest of 12 units on EPC record in the building, where floor areas span 51–170 m². The building's EPC ratings span F to C across 12 units on file.

Held since December 1997 — that's 29 years off the open market, well above the local norm. Only one transfer is on record with HM Land Registry, suggesting it has stayed in the same hands for a long time. Today's modelled estimate of £471,000 sits 698.3% above the 1997 sale of £59,000. On a £-per-square-foot basis, the last sale (£59/sq ft) was about 67.1% below the postcode norm. It lags the bulk of the postcode on energy efficiency (less efficient than 82% of similar EPCs).