20a, Bisterne Avenue, Waltham Forest, London, E17 3QS

20a is a three-bedroom semi-detached house in Waltham Forest, London, London (E17 3QS). It has a recorded floor area of 62 m² (around 666 sq ft), construction records dating it to 1930-1949 and council tax band B. The latest certificate (January 2010) shows a D (score 65), on the cusp of jumping into the C band. The rating has held steady at D across 2 certificates since October 2008. Between certificates, lighting went from Good to Very Good; while roof efficiency dropped from Average to Poor. The recommended improvements would push it to C (score 71). The latest certificate is from January 2010, so improvements made since then won't be reflected. At 62 m² this is the 9th smallest of 42 units on EPC record in the building, where floor areas span 31–167 m². The building's EPC ratings span F to B across 42 units on file.

Held since April 2010 — that's 16 years off the open market, well above the local norm. Today's modelled estimate of £366,000 sits 109.1% above the 2010 sale of £175,000. On a £-per-square-foot basis, the last sale (£263/sq ft) was about 19.3% below the postcode norm. At 62 m² it's 18.6% smaller than the typical home in the postcode (76 m² median across 41 EPCs). It lags the bulk of the postcode on energy efficiency (less efficient than 78% of similar EPCs).