KJ Tait

GOSH Sight and Sound Centre

Great Ormond Street Hospital
Project team
Sonnemann Toon

The Italian Hospital is a Grade II listed building in the London Borough of Camden that has undergone redevelopment to become the new Great Ormond Street Hospital Sight and Sound Centre. KJ Tait were instructed to provide the Energy Strategy for the proposed redevelopment that conforms with the Greater London Authority requirements on Major Redevelopments.


The building was assessed using IES VE to calculate what the building carbon emissions were before redevelopment. This found that due to inefficient systems and lighting, that there was a benchmark of 67kgCO2/m2, around 3 times higher than a new building would produce.


The first stage of the redevelopment was to investigate energy efficiency measures that could be incorporated. Using the thermal model, we assessed the payback of improving the U-value of the external wall by 0.27W/m2K by insulating the wall lining. This found that this small improvement in the U-value would only reduce carbon emissions by 2.4%, would take 136 years to payback and was therefore This was discounted as an initiative to be taken forward. In order to reduce the building’s reliance on energy intensive ventilation, a mixed mode approach was used where natural ventilation from the windows is used as much as possible. In testing this approach for the potential for the building to overheat, a CIBSE Guide TM52 assessment was carried out using Design Summer Year weather files.


Due to the historic nature of the building, there was limited scope to replace the glazing with new units. Therefore, secondary glazing was installed to mitigate the heat losses through the glazing. New energy efficient LED lighting was installed to further reduce the energy consumption. From these passive measures, there was a 52% saving in carbon emissions.


A small PV array was installed on the roof to comply with planning requirements to maximise PV and to ensure a security of electrical supply on site.


In total, a 53% reduction in the buildings carbon emissions was achieved by carrying out the redevelopment which allowed the project to receive planning permission.