4 Wall Hall Mansion, Wall Hall Drive, Aldenham, Watford, WD25 8BZ

4 Wall Hall Mansion is a two-bedroom end-of-terrace house in Aldenham, Watford, Watford (WD25 8BZ). It has a recorded floor area of 16 m² (around 172 sq ft), construction records dating it to 1900-1929 and council tax band G. At 16 m² this is the smallest unit on EPC record across the building (16–478 m²). The building's EPC ratings span E to C, with this unit at the bottom. On EPC score it ranks last in the building (54 versus a best of 77). The latest certificate (May 2015) shows an E (score 54), well below the UK norm with real room to improve. Earlier certificates rated it C (November 2008); the latest reading is 2 bands lower. The recommended improvements would lift it to C (score 73), a 2-band jump. The latest certificate is from May 2015, so improvements made since then won't be reflected.

It hasn't traded since May 2009, a hold of 17 years that's notably long for the area. That sale fell during the post-crash dip, which often skews comparisons against later neighbouring sales. At 16 m² it sits well below the postcode median (366 m² across 5 EPCs), making it one of the more compact homes locally. On energy efficiency it sits in the bottom 10% of properties in this postcode — significant headroom for improvement. Today's modelled estimate of £712,000 sits 78% above the 2009 sale of £400,000. On a £-per-square-foot basis, the last sale (£2,323/sq ft) was about 383.3% above the typical sold price in the postcode.