London local authority Waltham Forest has reused and ungraded 500 street lighting lanterns with LED using retrofit kits rather than replacing them.
‘We were looking to move to LED to improve efficiency but struggled to find a modern luminaire that matched the look and feel of what we already had,’ said Leo Cole, street lighting engineer at the London borough. ‘We didn’t want to replace these lanterns with standard fittings. They’ve become part of the character of the area. The shape and design are distinctive, and that was something we were keen to retain.’
Many of the borough’s lanterns feature a curved, architectural form that sets them apart from more typical ‘shoebox’ style luminaires.
While visually well suited to their surroundings, internally they relied on traditional lighting technology with higher energy consumption and increasing maintenance requirements.
Supported by funding from the Mayor of London’s Energy Efficiency Fund, the council explored how the lights could be upgraded without full replacement, reducing cost, disruption and material waste.
With a focus on improving efficiency while preserving the visual identity of residential streets, the project developed into a borough-wide retrofit programme.
The council’s term contractor, JB Riney, managed the planning, programming and installation of a bespoke LED retrofit solution manufactured by Acrospire, enabling the internal components of each lantern to be upgraded while retaining the original housing.
The process involved removing the existing optical system and control gear and installing a new LED light engine within the existing luminaire body. This approach preserves the external appearance of the lantern while delivering modern lighting performance.
A key stage in the project was the initial trial phase, where sample units were installed and assessed in a live environment. This allowed the council to evaluate light levels, uniformity and potential light intrusion into nearby properties before committing to a wider rollout.
To address concerns around backlight into residential windows, Acrospire designed and introduced a back shield, reducing light spill while maintaining effective illumination at street level.
Across the scheme, over 500 lanterns are being retrofitted, delivering a circuit wattage reduction of around 45 per cent compared to the previous installation.
Installation was carried out in situ, with each retrofit taking approximately five minutes per lantern.
The luminaires were specified at 3000K, providing a warmer light output in line with the council’s preferences for residential areas.
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