COVER STORY
Portsmouth’s Nicholson Gardens slashed heating energy by 36 % with VEXO’s S-BMS
Wireless & electrician-friendly: how
Retirement living may be about slowing down – but Nicholson Gardens is now racing ahead on energy efficiency. By replacing a dated boiler sequencer with VEXO’s Smart-BMS (S-BMS®) platform – and teaming it with 290 wireless Smart TRVs and other sensors – Portsmouth City Council has cut annual gas use by a quarter and heating- only consumption by more than a third. Here’s how the project delivered big-system performance on a modest budget, and what it means for consultants looking to decarbonise hard-to- treat stock.
The retrofit reality
Built in 1984, Nicholson Gardens comprises 49 studio flats over three storeys plus communal lounges, kitchens and corridors – a typical 3,400 m2 mix of continuous and intermittent heating loads. Two 150 kW boilers feed one variable- temperature (VT) circuit and a domestic hot-water (DHW) cylinder. Before 2021 the plant room relied on a conventional weather- compensating sequencer and direct-fired water heaters. Radiators were fitted with only manual TRVs and there was no feedback from occupied spaces.
Enter S-BMS – small box, big impact
VEXO has empowered the M&E contractor to replace the legacy controller with its S-BMS panel as well as the following wireless devices:
• Smart TRVs – reporting set-point, occupancy and demand in real time.
• Motion room sensors – temperature, motion and relative-humidity data every five minutes
• Window sensors – instantly inhibiting heat to stairwells when windows are opened.
Because everything is wireless, there was no intrusive chasing or containment: ideal for vulnerable residents and busy communal areas. Installation (including panel) was completed during scheduled summer shutdown maintenance.
Control strategies that cut carbon
S-BMS was commissioned remotely by the VEXO team and validated on-site by the mechanical & electrical contractor, thanks to the training, electrical diagrams and intuitive dashboards being all part of the service. Once heating demand starts, the system is able to implement strategies such as the following:
1. Demand-based boiler set-points Flow temperatures are trimmed continuously; the system drives to 80 °C only when the DHW cylinder calls, then drops to the VT requirement. That alone slashes standing losses from headers and distribution pipework.
2. Live weather compensation Degree-day data sets a VT curve of 30 – 70 °C between 20 °C and 0 °C ambient. Under part-load the S-BMS shaves further degrees in response to aggregate TRV demand.
3. Adaptive setbacks
In communal zones the S-BMS automatically reverts from 21 °C occupied to 16 °C setback, while motion sensors boost rooms such as TV lounges only when residents are present.
4. Resident empowerment without energy drift Within flats residents retain full control up to 28 °C, but the BMS can cap individual heads, reset nightly, or ignore outliers on hot summer days.
The headline numbers KPI
Pre- retrofit 2019/20
Total gas (kWh)
Heating energy (kWh)
CO2 saving 521,622 359,622
24 tonnes p.a.
*Weather-normalised to equal degree-days.
In plain terms, Nicholson Gardens now burns 132 MWh less gas every year – the equivalent of taking almost 30 UK cars off the road.
Payback – and then some
The gas savings translate to around £10,000 a year at today’s public-sector contract prices. With low-disruption installation and no new boilers required, simple payback for equipment and installation is well under four heating seasons. Crucially, residents report no comfort complaints; in fact, tighter control has reduced overheating in corridors. The project also received industry recognition, winning Energy Project of the Year – Residential in 2023, with great competition from the likes of Octopus Energy and Ilke Homes.
Why it works in sheltered housing – and beyond
Sheltered schemes combine domestic and commercial behaviours: permanently occupied flats flanked by spaces that may sit empty for hours. Traditional BMS platforms struggle because they sample only plantroom conditions. S-BMS turns every radiator into a sensor, creating a distributed mesh of thermal feedback. That makes the strategy equally relevant to hotels, student residences, hospitals and older offices where full valve replacement is viable but pipe- runs or asbestos risks rule out rewiring. Additionally, the latest Part L Building Regulations now mandates dwellings ≥150 m2 must have at least two independently-time-and- temperature-controlled heating circuits, which is easily achieved by an M&E Contractor installing an S-BMS panel at a fraction of the cost of traditional BMS systems and integrators.
A new way of installing BMS 1. Contractors submit the control
10 BUILDING SERVICES & ENVIRONMENTAL ENGINEER JULY 2025
specification. If there isn’t one, VEXO will write it based on the equipment required to control.
2. VEXO provides a quotation within 72 hours. A follow-up call is scheduled to review the purchase order, aligning both parties on equipment and description of operation. The order is the shipped within 8 weeks.
3. VEXO arranges a 1-day free installation & dashboard training at the contractor’s office. Includes 12-month certification card + e-learning resources.
4. The contractor performs the installation following the wiring diagrams provided specific to the installation.
5. VEXO supports commissioning remotely, collaborating with the contractor’s on-site team to validate system functionality.
Post- retrofit 2021/22*
389,083 227,083
Energy Saved
-25 % -36 %
6. The system is ready to be handed over to the incumbent facilities team with standard technical support available from VEXO
Lessons for the wider sector
• Don’t wait for the boiler swap. Water Quality and Controls first, new equipment second. VEXO’s renowned X-POT, combined with our S-BMS and LoRaWAN devices can deliver immediate savings and primes the system for low- temperature heat sources.
• Data builds the business case. Post- installation dashboards clearly separate DHW base-load from space-heating demand – vital evidence when seeking SALIX or PSDS funding.
• Scalable beats traditional. A 300-room university hall or a 20-bed care home can adopt the same architecture, scaling panels and devices accordingly.
At a glance – S-BMS benefits
• Up to 36 % heating-energy reduction proven in live schemes
• Carbon, cost and compliance gains with minimal resident disruption
• Wireless retrofit in days, not weeks • Granular control down to individual radiator
• Built-in analytics and remote firmware updates
• Proven technology with over 30 installations in the UK
Not for Every Building. Perfect for Most.
BMS built for the majority — simple, smart, and scalable. Whether you are refreshing an existing BMS, planning a heat-pump transition or simply chasing kilowatt-hours ahead of the next EPC milestone, VEXO’s S-BMS provides an agile route to measure, manage and monetise plantroom efficiency.
BOOK A DEMO
www.vexoint.com |
technical@vexoint.com | +44 (0) 1767 500 150
VEXO International (UK) Ltd. S-BMS® and VEXO® are registered trademarks. LoRaWAN® is a mark used under licence from the LoRa Alliance.
Read the latest at:
www.bsee.co.uk
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38
