According to Official Guinness Records,
Deborah Morris (UK) cleaned three standard 1.14 m x 1.14 m (45 x 45 in) office windows set in a frame with a 300 mm (11.75 in) long squeegee and 9 litres (2 gal; US 2.37 gal) of water in 16.28 sec at the Cleaning Show 2011 held at NEC, National Exhibition Centre, in Birmingham, UK, on 3 March 2011. A base time of 13.28 sec was achieved but 3 sec penalty was incurred.
For a complete list of 2011 records, please visit 2011 Guinness Records in United Kingdom.