The Grade II* Listed Blue Mills in Witham, Essex dates back to the 18^th century. However, its history goes back considerably further. The original 16^th century cottage is attached to a Georgian house (at the front), a sequence of early Victorian extensions, and a later Victorian house in 1872 (at the rear). The recent owners have lived in Blue Mills for almost 20 years and required a thermal solution, with acoustic benefits to make their home at the mill more thermally comfortable. 22 windows have been treated using a number of window styles: fixed light, vertical sliding and side-hung casements. Two windows in the wood-panelled room were treated with the Series 47 hinged casement system which was able to sit tight behind the wooden shutters, allowing their continued operation. The aluminium profiles were coloured in a woodgrain finish which colour matched the existing surrounds perfectly.  The stunning Billiard Room was fitted with four Series 45 side hung casements. Additionally, a Series 25 vertical sliding unit was installed as one of the windows in the Billiard Room was larger than the other. The front door was treated with a mixture of two Series 42 fixed light units on either side of a Series 41 double-side hung casement, whilst the rear door was fitted with a Series 41 Side hung casement.