21 Blake House, Gunwharf Quays, Portsmouth, PO1 3TH

21 Blake House is a two-bedroom detached house in Portsmouth (PO1 3TH). It has a recorded floor area of 109 m² (around 1173 sq ft), construction records dating it to 1996-2002 and council tax band E. The latest certificate (November 2025) shows a C (score 72). The rating has held steady at C across 2 certificates since October 2010. Between certificates, lighting went from Poor to Good; while window efficiency dropped from Average to Poor and hot-water efficiency dropped from Good to Very Poor. Main heating runs on electricity. At 109 m² this is the 37th smallest of 43 units on EPC record in the building, where floor areas span 52–155 m². The building's EPC ratings span E to B across 43 units on file. Other recorded features include notable views.

Untraded for 15 years, with the last transfer in December 2010. At 109 m² it's 16% larger than the typical home in the postcode (94 m² median across 42 EPCs). Across 2002–2010, sale prices on this property compounded at 1.6% per year. Today's modelled estimate of £654,000 is 34.8% above the 2010 sale price. On a £-per-square-foot basis, the last sale (£413/sq ft) was about 21.6% above the typical sold price in the postcode.