A thermal modelling analysis report was carried out on the Deliotte Building, 3 Victoria Square, Victoria Street, St Albans in order to determine its current levels of peak heating and cooling loads. These were then compared against the estimated peak heating and cooling loads for the building if the old existing windows were replaced by new windows to meet the minimum performance of Approved Document L with a U-value of 2.2 W/m2.K.
The image below shows the heat loss per m2 for each of the different construction elements of the building. It can be clearly seen within the first half of the image that the existing windows are losing a considerable amount of heat in comparison to the other construction elements. The second half of the image shows that when the improved windows are installed, the heat loss experienced throughout the construction elements is now much more uniform and a heat energy saving is made.
The peak heating loads show that on average a 34.7% saving could be made by improving the windows throughout the building. As the air leakage rate for the building would also be improved by replacing the old windows, heat loss savings are also possible in the rooms that do not directly contain any windows.
The peak cooling loads show that on average a 13.7% saving could be made by improving the windows throughout the building.