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

18 Blackwell House is a two-bedroom property in Nash Mills Wharf, Hemel Hempstead, Hemel Hempstead (HP3 9FX). It has a recorded floor area of 48 m² (around 517 sq ft), construction records dating it to 2012-2021 and council tax band D. The latest certificate (December 2025) returns a B (score 82), comfortably above the UK average. When first surveyed in October 2015 the rating was C, the property has climbed 1 band since. Between certificates, hot-water efficiency went from Very Poor to Average and main heating went from Very Poor to Poor; while wall efficiency dropped from Very Good to Good and window efficiency dropped from Very Good to Average. Main heating runs on electricity. At 48 m² this is the 5th 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 top. Other recorded features include a balcony.

At 48 m² it's 27.3% smaller than the typical home in the postcode (66 m² median across 35 EPCs). On energy efficiency it sits in the top 10% of properties in this postcode. On a £-per-square-foot basis, the last sale (£600/sq ft) was about 38.9% above the typical sold price in the postcode. 11 years since the last transfer (December 2015).