Establishing a costed pathway to net zero with East Kent University Hospitals NHS Foundation Trust

In October 2023, the NHS Net Zero Building Standard became mandatory for all new-build, refurbishment and retrofit schemes above £25M across NHS England.  The Standard is a critical measure to address climate change impacts and ensure sustainable, quality care for patients. Under the project management of Archus, Square Gain co-authored the Standard, which is aligned with BREEAM.

Refurbishment and retrofit of existing buildings will play a huge role in the NHS England’s plans for achieving net zero carbon emissions by 2040. With the NHS’ limited financial resources, maximising the benefit of these investments will be key.

Greg Chant-Hall, Director at Square Gain, said: “On larger projects it can be difficult to know where to start.  We wanted to avoid making blanket retrofit changes across the whole building and instead, focus on interventions that would deliver the best return on investment.”

Informing retrofit options

Square Gain wanted to test how the Standards’ requirements for decarbonisation could be achieved on a pilot project at East Kent University Hospitals Foundation Trust.  The Trust selected their ‘most challenging’ building, the aptly named 1937 Building, which had changed very little since its original construction.

Working closely with 2Gether Support Solutions, who provide facilities services at the hospital, we assessed the extent of heat loss and air leakage for individual rooms, identifying problem areas that could be focused on and a ‘one size fits all’ approach was avoided. The aim was to save the hospital Trust money and to decarbonise in the most cost-effective way.

Air permeability

It was vital hospital operations were not interrupted by our activities. We partnered with Build Test Solutions’ and their unintrusive Pulse system allowed patients and hospital staff to remain in the building during air-tightness testing.

Over two days a total of 23 rooms were tested including wards, staff spaces, storage rooms, and even multi-faith accommodation.  The data was plotted against a series of parameters, including the floor, external walls and envelope areas, volume and glazing ratio. Results found there was no common trend between the most problematic and the best performing rooms, showing the importance of a tailored retrofit approach in each room.

Luke Smith, Managing Director at Build Test Solutions, commented: “Minimising uncontrolled air leakage from a building can reduce heating and cooling demands by over a third. It also significantly improves the comfort and well-being of patients, by reducing draughts and unwanted air movement.  Ensuring rooms are airtight but also supplemented with controllable ventilation is key to maintaining safe and well-regulated internal conditions.”

Heat loss

We partnered with the UCL’s Bartlett School of Architecture to undertake detailed laser scans and thermal images of the building envelope. This enabled points of weakness in the building fabric to be identified and plans for remediation measures focused on the areas of greatest need, including poorly performing windows, thermal bridging, water ingress and missing or inadequate performing insulation.

Energy analysis

The team undertook a detailed analysis of energy usage through interrogation of site-wide Estates Return Information Collection (ERIC) data, BMS and building-specific utility consumption via billing data.  The 1937 Building did not have sub-metering installed and the primary electricity and gas meters for the building were analogue, and therefore reliant on manual meter readings.  Energy use for the building was higher on the 1937 Building than the average energy usage per m2 across the site.

Green technologies

Working with our partners Carbon Free Group CIC, a wide range of potential green technology interventions were investigated, ranging from different types of solar electrical and thermal capture and storage, micro-wind technologies, and heat pumps.  The analysis identified a suite of suitable technologies, and informed the development of the NHS England Net Zero Capital Planning Tool (NZCPT). The NZCPT provided three costed outputs for the Trust with options to achieve 50% carbon reduction, 80% carbon reduction and net-zero carbon.

Greg Poole, Associate Director at Square Gain, said: “By having specific data from each tested room, we were able to assess the rooms that had the worst air leakage and most notable thermal weak spots.  It sounds simple but we quickly found a number of quick fix issues such as windows that would not fully close and areas of missing insulation in the walls and roof.”