The £22m remodelling and refurbishment of the 1930s civic building and 1970s office extension to Wiltshire County Hall in Trowbridge was undertaken to consolidate the majority of Wiltshire Council's 95 offices into four hubs. A major requirement was to reduce the energy consumption by 40%. It is also one of the refurbishment projects within the UK on target for a BREEAM 'Excellent' rating. The designs needed to be engineered to meet the thermal requirements. The solution for most windows was a matching balanced sash design that permits access to the existing window. Some of the windows were very large, up to 3.5m high and 1.6m wide, and a heavy duty frame from the Series 90 range was required to support the glass sizes. Most were glazed with a low emissivity glass that markedly improves the thermal efficiency. In the Council Chamber, which has some of the largest windows, a single monumental hinged casement design was chosen. This was a big challenge as each casement weighs about 100kg. The Series 50 range was specified with a bronze anodised finish to complement the panelling.