Efficiently preserving Herts County’s heritage

The solution

HCC has many heritage lanterns throughout the county, complementary to their historic architectural landscape. As the original manufacturer of many of the original lanterns, some dating back over 30 years, DW Windsor were delighted to be awarded the tender to supply the first phase of the programme.

The focus of the project was to reduce the cost of energy and maintaining existing lanterns by converting them to more efficient LEDs, while meeting current day design requirements, where possible, or matching the previous installation.

Alan Grant, Design & Development Director, ‎DW Windsor explains,

Converting a heritage lantern to LED is not as straightforward as it sounds. Heritage lanterns are fully enclosed and there is no escape for any heat generated by the light source. We developed an innovative solution for this by creating a thermal path to direct the heat outside of the luminaire, allowing us to increase the drive current and lumen package to meet the lighting performance requirements.

We worked with HCC and Ringway to identify, from photos, which spec of product was currently installed and therefore which could be retrofitted instead of replaced, saving the council the expense of complete new lanterns in some locations.

Challenges faced onsite included difficulties in opening products that had been untouched for 30 years or more and removing lanterns from brackets, DW Windsor and Ringway worked together to solve these minor difficulties.

The LED retrofit and new heritage luminaires use much less energy than conventional street lights and have improved colour rendering. Once the project is complete, HCC anticipates the conversion will generate annual savings of up to £660,000. They have also opted to implement a CMS system to allow them to dim the lights outside of peak hours, further increasing the energy savings, which in turn reduces costs.