12c, Belsize Square, London, NW3 4HT

12c is an end-of-terrace house in London (NW3 4HT). It has a recorded floor area of 139 m² (around 1496 sq ft) and construction records dating it to before 1900. The latest certificate (January 2019) shows a D (score 60), on the cusp of jumping into the C band. The rating has held steady at D across 2 certificates since December 2008. Between certificates, window efficiency went from Very Poor to Poor and lighting went from Very Poor to Very Good; while roof efficiency dropped from Average to Very Poor and hot-water efficiency dropped from Good to Average. The recommended improvements would push it to C (score 77). At 139 m² this is the 46th smallest of 52 units on EPC record in the building, where floor areas span 39–211 m². The building's EPC ratings span F to C across 52 units on file.

At 139 m² the property is well over the postcode median (94 m² across 74 EPCs), placing it in the larger end of the local stock. Across 2006–2016, sale prices on this property compounded at 12.8% per year. On a £-per-square-foot basis, the last sale (£1,227/sq ft) was about 107.2% above the typical sold price in the postcode. Last sold in March 2016, so it's been off the market for around 10 years.