One Threadneedle Street : Nationwide Building Society
Nationwide Building Society chose to completely refurbish its seven-story London headquarters at One Threadneedle Street after the building became vacant during the COVID-19 pandemic. As part of this comprehensive modernisation project, main contractor ISG engaged The REGEN Initiative to survey the entire facility and deliver a complete LED lighting retrofit proposal
Original Luminaires
One Threadneedle Street features seven floors of commercial office space equipped with a mix of linear and grid lighting systems. The original installation included circular T5 fixtures in the stairwells, 21W T5 luminaires in the meeting rooms, and ceiling-tile grid lights (Mellowlight 4) housing 1 x 54W T5 fluorescent lamps. The linear lighting consisted of long, continuous rows of 35W and 54W T5 fluorescent lamps. These were fixed to overlapping, removable trays and recessed within extruded aluminium trunking.
To upgrade the system, REGEN manufactured bespoke LED gear trays. These custom trays allowed contractors to retrofit the existing luminaires directly in situ, eliminating the need to remove any fixtures from the site
Linear office lighting
Custom LED modules were manufactured to fit seamlessly end-to-end, replacing the overlapping layout of the original fluorescent lamps to deliver perfectly uniform, continuous linear lighting. To ensure seamless control, the system pairs Tridonic LED boards and DALI drivers with the site's upgraded Simmtronic Lighting Control System
Stairwell & Meeting Room Lighting
The circular stairwell luminaires were upgraded from circular T5 lamps to Tridonic area boards, while the meeting room linear fixtures were retrofitted by replacing the 21W T5 lamps with short LED modules.
Modular Luminaire upgrade
The 1200 x 300mm 1 x 54W T5 Fluorescent Mellowlight 4 luminaires were upgraded by placing a single LED gear tray centrally beneath the existing prismatic optic. Designed for in-situ installation, the new LED module minimised handling time. Liteplan lithium emergency kits were also integrated during the upgrade.
Final Result
The project achieved exceptional uniformity and consistent, homogeneous illumination, featuring true colour rendering driven by tight Tridonic LED chip binning.
The first-class installation was executed by ECO-Fix UK, who installed the retrofit modules floor by floor while managing all access equipment, PPE, and RAMS. Lumicom Ltd handled sustainable waste management, collecting and recycling all waste materials at the end of works on each floor. The entire project was expertly managed by the REGEN Initiative.
Project Performance Metrics
- 25,532 kg/CO₂e Avoided
- 69% carbon avoidance in remanufacture
- 1,101 Luminaires remanufactured
- 42% Energy Savings across the project
- In-situ LED retrofit of T5 fluorescent to LED
- On site installation Light levels maintained
- Emergency lighting upgraded to be compliant Linked into existing BMS system
- Every retrofit gear tray tested and warranted
