13a, High Street, Sunninghill, Ascot, SL5 9NQ

13a is a semi-detached house in Sunninghill, Ascot, Ascot (SL5 9NQ). It has a recorded floor area of 64 m² (around 689 sq ft), construction records dating it to 1900-1929 and council tax band B. The latest certificate (November 2015) shows an E (score 53), well below the UK norm with real room to improve. When first surveyed in February 2009 the rating was G, the property has climbed 2 bands since. Between certificates, roof efficiency went from Poor to Good, window efficiency went from Very Poor to Good and main heating went from Poor to Average; while wall efficiency dropped from Average to Very Poor and hot-water efficiency dropped from Poor to Very Poor. The recommended improvements would lift it to C (score 77), a 2-band jump. Main heating runs on electricity. The latest certificate is from November 2015, so improvements made since then won't be reflected. At 64 m² this is the 6th smallest of 10 units on EPC record in the building, where floor areas span 48–96 m². The building's EPC ratings span E to B, with this unit at the bottom. On EPC score it ranks last in the building (53 versus a best of 81).

On energy efficiency it sits in the bottom 10% of properties in this postcode — significant headroom for improvement.