Flat 3, 51 Belsize Park Gardens, London, NW3 4JL

Flat 3 is a semi-detached house in London (NW3 4JL). It has a recorded floor area of 34 m² (around 366 sq ft), construction records dating it to 1900-1929 and council tax band D. At 34 m² this is the smallest unit on EPC record across the building (34–89 m²). The building's EPC ratings span D to C, with this unit at the top. The latest certificate (March 2020) shows a C (score 69), just inside the C band. The rating has held steady at C across 2 certificates since May 2010. Between certificates, wall efficiency went from Very Poor to Poor and lighting went from Very Poor to Very Good; while main heating dropped from Very Good to Good.

At 34 m² it sits well below the postcode median (72 m² across 25 EPCs), making it one of the more compact homes locally. Across 2002–2017, sale prices on this property compounded at 6.2% per year. On a £-per-square-foot basis, the last sale (£1,325/sq ft) was about 130.6% above the typical sold price in the postcode. Last sold in December 2017, so it's been off the market for around 8 years.