Prefect Controls has long known that its revolutionary SmartTank saves energy and reduces water waste.
Now, an extensive study of accurate data of utilities consumption from a 393-bed property – (‘Building A’) – in the East Midlands has been benchmarked against sites where SmartTank has been operating for several years. The analysis presents a compelling investment case by revealing that SmartTank consumes 1.5 times less energy than conventional cylinders!
Designed for energy managers seeking carbon and cost reductions without major disruption, SmartTank offers a fast-payback upgrade to traditional immersion tank systems.
Energy Savings
Current monitoring shows the hot water system at ‘Building A’ consumes 501 kWh per bed per year.
Benchmarking indicates that a long-term achievable performance level is 369 kWh per bed per year.
This represents an estimated 26% reduction in energy use per bed. Across ‘Building A’, this reduction equates to tens of thousands of kilowatt-hours saved annually, producing substantial operational cost and carbon savings.
Water Waste Reduction
Water consumption in student accommodation is typically 125 litres per person per occupied day according to CIBSE guidance.
SmartTank enhances water efficiency through an array of integrated sensors capable of detecting: leaks and persistent drips, stuck or passing valves, continuously running outlets, Tundish discharge or other abnormal water escape.
By identifying faults early, maintenance teams can intervene before minor issues escalate into significant water losses or property damage.
The benchmark has been applied alongside occupancy data captured via the system. It estimates the volume of water that would have been consumed had SmartTank been in place and identified faults, rectifying them in a timely manner. The difference between actual and benchmark-adjusted consumption forms the basis of the projected water savings.
Verifiable reductions
Typical annual reductions are shown to be:
- Electricity (kWh) saving – 52,000 kWh
- Electricity cost saving – £13,280
- Water (m³) saving – 12,800 m³
- Water cost saving – £32,198
- 6+ tonnes CO2 (energy)**
- 13+ tonnes CO2 (water)***
Operational and Compliance Efficiency
SmartTank continuously records temperature data and system performance, automatically generating compliance and audit reports. This provides several operational benefits: Reduced manual temperature checks, automated compliance reporting for water hygiene regimes, and exception-based maintenance rather than routine inspections. For example, removing a monthly 15-minute manual inspection per tank can save thousands of pounds per year in labour costs across medium-to-large residential sites.
Optimiser+SmartTank provides guidance about maximising the performance of the water heating system. It presents real-time insight to Energy use, Water Safety, High Consumers, Service Faults, Sensor Faults and Tank Cupboard Humidity.
A total of six temperature sensors and an additional 8 sensors/meters monitor conditions both inside and outside the tank, from supply volume, to incoming and outgoing water temperature, pressure issues, to escape of water. No other hot water cylinder captures the amount of data, automatically analyses and then provides guidance for improved performance.
Carbon and ESG Benefits
Typical annual savings from a SmartTank upgrade can be seen overleaf. These measurable reductions support ESG reporting, carbon-reduction commitments, and long-term net-zero strategies.
Additional Benefits
SmartTank can also:
- Participate in demand-side flexibility programmes
- Shift heating away from peak grid periods
- Enable continuous optimisation of
- temperature setpoints
- Provide granular data for portfolio-wide energy management
These benefits are often treated as intangible and therefore not included in base ROI calculations.
A Smarter Upgrade
SmartTank is particularly well suited to buildings with:
- Immersion-based hot water systems
- Multi-occupancy with variable usage patterns
- Ageing hot-water infrastructure
- Strong sustainability or carbon-reduction targets
Built on the trusted Gledhill cylinder platform, SmartTank is factory fitted with integrated Prefect controls, pre-plumbed and pre-wired. It connects directly to electricity, water supply, and the Prefect Irus building services management portal.
Through precise control, real-time monitoring, and automated data analysis, SmartTank provides full system visibility and intelligent responses to changing demand.
The high-performance upgrade not only reduces utilities consumption, but lowers operating costs, and environmental impact while improving compliance and building performance for modern residential buildings.
Assumptions used in this example
This example uses the 2024-25 academic year for the analysis period as this timeframe saw more standard occupancy, as the property is currently seeing reduced occupancy from September 2025 onwards.
Electricity: 25.6p/kWh
Water: £2.50/m³
Annual inflation: 5%
*Labour: £20/hour
**Annual Carbon Reduction (Scope 2) – 6.4 Tonnes (at 2024 UK grid intensity of 124gCO2/kWh)
***Annual Carbon Reduction (Scope 3) – 13.5 Tonnes (at 2025 BEIS/Defra intensity of 1.05kgCO2 per m3)
