Edwards Hart are working on energy efficiency and sustainability issues concerning the conversion of Listed buildings into apartments in Manchester for Beech Holdings. Edwards Hart are approaching this in a holistic way by analysing the existing building fabric and its energy performance characteristics. This includes the affects that the condition of the buildings may have on their energy performance. It also involves calculating the existing U values by working out the exact construction and composition of each buildings enclosure, extracting materials from them and testing the materials to gauge their thermal conductivity values. Methods of retrofitting are also explored, and calculations and modelling performed to gauge their affects in terms of possible risks and improved energy performance. Whilst this work is very technical there is also the need for measuring its effects on the significance of the buildings and here Edwards Hart also undertake heritage impact assessments.