15 Blackwell House, The Embankment, Nash Mills Wharf, Hemel Hempstead, HP3 9FX

15 Blackwell House is a property in Nash Mills Wharf, Hemel Hempstead, Hemel Hempstead (HP3 9FX). It has a recorded floor area of 72 m² (around 775 sq ft), construction records dating it to 2012 onwards and council tax band D. At 72 m² this is the 24th smallest of 36 units on EPC record in the building, where floor areas span 46–83 m². The building's EPC ratings span D to B, with this unit at the bottom. On EPC score it ranks last in the building (59 versus a best of 87). The latest certificate (March 2026) shows a D (score 59), a step below the typical UK home. Earlier certificates rated it C (October 2015); the latest reading is one band lower. Between certificates, wall efficiency dropped from Very Good to Good and window efficiency dropped from Very Good to Average. The recommended improvements would push it to C (score 76). Main heating runs on electricity. This certificate was lodged in the last six months, so the rating reflects current condition.

A recent sale: £235,000 in July 2025. At 72 m² it's 16.1% larger than the typical home in the postcode (62 m² median across 35 EPCs). It lags the bulk of the postcode on energy efficiency (less efficient than 89% of similar EPCs). Across 2015–2025, sale prices on this property compounded at -3.4% per year. Today's modelled estimate of £311,000 is 32.3% above the 2025 sale price. On a £-per-square-foot basis, the last sale (£303/sq ft) was about 30.2% below the postcode norm.