Flat 3, 7 Birkenhead Avenue, Kingston Upon Thames, KT2 6RW

Flat 3 is a one-bedroom semi-detached house in Kingston Upon Thames (KT2 6RW). It has a recorded floor area of 52 m² (around 560 sq ft), construction records dating it to 1900-1929 and council tax band D. At 52 m² this is the smallest unit on EPC record across the building (52–79 m²). The building's EPC ratings span D to C, with this unit at the top. On EPC score it ranks first in the building (76 versus a worst of 56). The latest certificate (July 2016) shows a C (score 76), near the top of the C band. When first surveyed in March 2014 the rating was D, the property has climbed 1 band since. Between certificates, wall efficiency went from Very Poor to Good, roof efficiency went from Very Poor to Good and lighting went from Very Poor to Very Good.

Held since March 1999 — that's 27 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 £341,000 sits 348.7% above the 1999 sale of £76,000. On a £-per-square-foot basis, the last sale (£136/sq ft) was about 69.7% below the postcode norm. At 52 m² it's 19.4% smaller than the typical home in the postcode (65 m² median across 8 EPCs). Its energy rating outperforms most of the postcode (better than 88% of similar EPCs).