Efficiently preserving Herts County’s heritage

The challenge

Hertfordshire County Council (HCC) have an ongoing commitment to maintain and improve roads for the benefit of all Hertfordshire residents. This includes key factors such as maintaining good visibility, safety and keeping energy bills low. Like many other counties HCC take a forward-thinking approach to lighting; rolling out an LED programme to replace their 110, 000 conventional light points.  After tackling their functional street lighting, HCC shifted their focus to their heritage luminaires. Which raised several challenges in the process.

Clients and partners


  • Client logo Ringway Jacobs 2 H160px


    Ringway Jacobs

Key project requirements

  • To retrofit LED light engines into a minimum of 60% of existing heritage stock.
  • Identify lanterns that were suitable for retrofit.
  • Meet current lighting design requirements where possible – with existing column positions.
  • Match previous installation light levels.

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.

" We are delighted to be working with DW Windsor on this large, complex project. Our heritage lighting will benefit from their new high quality LED array lighting.  DW Windsor are technically agile, reactive and able to deliver a first class, cost-effective service "

 Jonathan Watt, Business Manager and Project Leader for Ringway

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