23a, Langley Road, Watford, WD17 4PR

23a is a detached house in Watford (WD17 4PR). It has a recorded floor area of 36 m² (around 388 sq ft), construction records dating it to 1900-1929 and council tax band B. At 36 m² this is the 2nd smallest of 7 units on EPC record in the building, where floor areas span 36–60 m². The building's EPC ratings span E to D, with this unit at the bottom. On EPC score it ranks last in the building (45 versus a best of 61). The latest certificate (March 2020) shows an E (score 45), well below the UK norm with real room to improve. Earlier certificates rated it C (March 2010); the latest reading is 2 bands lower. Between certificates, hot-water efficiency went from Average to Good; while wall efficiency dropped from Good to Very Poor and roof efficiency dropped from Average to Very Poor. The recommended improvements would push it to D (score 57).

Held since March 2010 — that's 16 years off the open market, well above the local norm. Across 1998–2010, sale prices on this property compounded at 19.7% per year. On a £-per-square-foot basis, the last sale (£994/sq ft) was about 279.6% above the typical sold price in the postcode. At 36 m² it's 17.2% smaller than the typical home in the postcode (44 m² median across 6 EPCs).