A practical route to improved performance

Improving the environmental conditions within NHS and healthcare estate buildings – while reducing operating costs and carbon emissions – is an increasingly critical focus for NHS Estates teams, healthcare engineers, and Sustainability leads. With the NHS committed to achieving Net Zero by 2040 for direct emissions, Vincent McMonagle, MEP Clerk of Works at 6RG, says the need for precision, evidence-led interventions in building performance is ‘more important than ever’.

For Estates and Facilities managers working across both clinical and non-clinical settings, delivering occupant comfort (especially in patient-facing spaces) while controlling costs is a balancing act. Rising energy prices, tighter capital budgets, and growing scrutiny of public sector performance, demand new approaches.

A practical route begins with understanding how the building’s MEP (Mechanical, Electrical, and Plumbing) systems are truly performing. As Lord Kelvin famously said: “If you can measure it, you can improve it.” Capturing an accurate ‘fingerprint’ of an NHS building’s services guides performance expectations, and provides the foundation for informed, measurable improvements in comfort, operational efficiency, and carbon reduction.

• Step 1: Create a fingerprint of the MEP system

This initial stage is non-intrusive: observe and record system performance ‘as is’ without initiating adjustments. This baseline snapshot will serve as the benchmark for future improvement. The key driver of this stage is to resist fixing or adjusting the found systems; the task is to get a complete picture of what is happening, and then make the remediation plan.

NHS Estates staff and building maintenance engineers play a key role at this stage; their lived experience and operational insights often reveal recurring comfort issues or system anomalies not evident in BMS data alone. A ‘no-blame’, collaborative environment is vital to ensuring that knowledge-sharing is equally prioritised with fault-finding.

Key system elements to fingerprint and record include:

• BMS data: Setpoints, schedules, overrides, and trend logs across heating, ventilation, and air-conditioning systems.
• Water flow rates: In heating and chilled water circuits.
• Airflow rates: Supply/extract volumes versus design criteria.
• Temperature zoning: Identifying hot/cold spots across wards, admin areas, theatres, and waiting spaces.
• Plant asset register: Equipment age, commissioning status, and current condition (e.g., AHUs, pumps, boilers, chillers, and VAVs, etc.).
• Updated schematic drawings of MEP systems.

• Step 2: Evaluate energy use by volume, not cost

With energy procurement across NHS Trusts often managed via framework contracts, cost-based analysis can be misleading. Instead, focus on energy volume to benchmark performance:

• Gas consumption (kWh or m³).
• Electricity consumption (kWh).

Gather 12 months of data from energy bills, AMR (automatic meter reading), or Building Management Systems. This volume-based data will form a stable, year-on-year comparison, and is essential for carbon reporting and compliance.

• Step 3: Compare against design and commissioning data

Review the building’s fingerprint against the original design intent, specifications, and any available commissioning records. Common issues in NHS buildings include:

• Incorrect or drifted setpoints.
• Unnecessary operation outside core hours (e.g., unoccupied offices, waiting areas, etc.).
• Poor flow or balance due to valve degradation or fouling.
• Simultaneous heating and cooling, especially in older estate blocks
• Outdated BMS control sequences.

This stage identifies clear, actionable items aligned with Specifications and SFG20 maintenance requirements.

• Step 4: Remediate and maintain a steady state

Following the fingerprint analysis (step 1,2,3), targeted remediation should be planned within existing PPM or cyclical works. Actions may include:

• Replacing faulty actuators or recalibrating sensors.
• Rebalancing systems to achieve even distribution.
• Resetting BMS control logic to reflect building use.
• Re-insulating plantroom pipework or updating AHU control strategies.

After implementing improvements, maintain the building in a stable operational state, with active monitoring and BMS trend reviews to detect drift or regression.

• Step 5: Re-measure and assess improvement

After 12 months, re-assess gas and electricity consumption by volume, and compare with the initial baseline. If usage has dropped, and comfort standards (temperature, air quality) have been maintained or improved, the intervention can be declared successful — both operationally and environmentally.

If no improvement is seen, the data still serves a vital role. It provides an evidence base for:

• Capital investment cases (e.g., replacing legacy boilers with heat pumps).
• Building fabric upgrades (windows, insulation).
• Deploying advanced energy analytics or controls.

Poorly performing HVAC and domestic hot water systems are a major source of avoidable carbon emissions in NHS buildings. Common faults like unbalanced circuits or stuck valves can quietly waste thousands of kWh per year. Several UK-based organisations, including the Carbon Trust, CIBSE (the Chartered Institution of Building Services Engineers), and BEIS (the Department for Business, Energy & Industrial Strategy), have published studies and guides that broadly support the types of savings mentioned.

1) Carbon Trust — HVAC Energy Efficiency Guides: Pump energy savings of 10—20% are often cited in guides focused on low-cost energy efficiency measures. Improved hydronic balancing and variable speed drives (VSDs) for pumps are key.

2) CIBSE Technical Memoranda (e.g. TM39, TM61, TM65): CIBSE recognises that eliminating simultaneous heating and cooling (often via better control strategies or recommissioning) can yield 15—30% gas or heat savings.

3) BEIS research and Public Sector Decarbonisation: BEIS-funded pilots under the Public Sector Decarbonisation Scheme (PSDS) and Energy Technology List include case studies showing 5-10% energy reductions from building management system (BMS) improvements alone.

Given that NHS buildings still rely heavily on gas heating, these changes can make a significant contribution to Net Zero delivery.

Conclusions: evidence-based action for NHS estates

Improving comfort and lowering running costs in NHS buildings doesn’t require guesswork or expensive innovation. It starts with structured measurement, using existing systems and the knowledge of on-site engineers. At estate/campus scale it is really helpful to have a baseline energy use intensity (kWh per m2 of usable floor space) and, if possible, by space use (e.g. ward, clinic, theatre, labs, workshops, retail, offices, imaging MRI, CT, sterilisation, etc).

This means that area sub-meters are very usefully assessing performance across buildings by activity type to determine which areas of the building might be problematic, and so prioritise remedials.

By fingerprinting MEP systems, comparing actual performance to design standards, and acting on the findings, NHS Trusts can achieve tangible, auditable improvements in both patient comfort and carbon emissions.