Decarbonising a Hard to Heat London Tram Depot with Infrared Heating
“Already, our staff wellbeing is incredibly high and people are very, very happy with them”.
Transport for London (TfL) is progressing a major heat decarbonisation and energy efficiency programme as part of its wider carbon-reduction strategy and the Mayor’s ambition for a net-zero London by 2030. A key element of this effort is the transformation of heating systems across its large operational sites, many of which have historically relied on fossil-fuel technologies.
TfL has partnered with Vital Energi and at the Therapia Lane tram depot in Croydon. InterLED, the commercial contracts division of Herschel Infrared, was appointed to deliver a fully electric infrared radiant heating and control solution.
Fully installed by InterLED in September-October 2025, the project showcases how infrared technology can replace gas-based convection heating systems in challenging industrial environments, reducing emissions while improving human comfort.
Decarbonising hard to heat buildings with infrared: Watch this case study testimonial video showing the infrared heaters installed throughout the tram depot and hear the client feedback on the installation.
Project Summary
Supply and install of sixty infrared heaters (Herschel Advantage and Herschel Vulcan infrared heaters) throughout TfL Therapia Lane tram depot, whilst keeping the site fully operational.
Total space: 2400sq Metres (26,000 sq feet)
• Main shed: 100M x 20M;
• Workshop and Bogey area: 35M x 11m.
Specification
InterLED (Herschel Infrared’s commercial contracts and lighting division) worked closely with TfL and the Vital Energi project team to assess the depot’s heating needs. The Therapia Lane depot operates 24/7, supporting various Tram maintenance functions across multiple loading bays, pits and workspaces, each with distinct heating requirements. To meet these diverse and complex conditions, InterLED carried out extensive modelling of optimal heater positioning, zone controllability, and required human comfort levels. There was also a limit on power consumption to factor into the specification, practical limitations of heater positioning and power cable runs, aesthetics and safety to consider.
High performance, UK-manufactured longwave Herschel Advantage heaters were chosen along with low glare, shortwave Herschel Vulcan heaters.
This choice of different heater types ensured that areas requiring instant, on-demand heating, such as workstations that are infrequently occupied, were effectively heated as required, whilst other heaters were specified to contribute to the overall ambient temperature on a timed/temperature setting. This allowed comfort and efficiency to be optimised based on workflow patterns and controllability demands.
The full specification of infrared heaters (replacing a gas blower system) included:
12 x Herschel Advantage 1.95kW Heaters
13 x Herschel Advantage 2.4kW Heaters
18 x Herschel Advantage 4.8kW Heaters
17 x Herschel Vulcan 6S 6kW Heaters
Smart Controls for Carbon and Cost Management
All heaters are operated through a UK-manufactured Herschel control system. This innovative platform enables:
• Zonal heating control
• Timed scheduling
• Energy monitoring for ongoing carbon-reduction tracking
• Fault-finding and diagnostics
Infrared’s zonal capabilities are particularly useful in large transport maintenance facilities. By directing heat only where and when it is required, significant reductions in both energy consumption and carbon emissions can be achieved compared to heating the entire volume of air. The heaters radiate heat outwards and downwards, ensuring that operatives remain comfortable within the effective radiant area even when ambient air temperatures fall below minimum workplace thresholds due, for example to open depot doors.
The InterLED project team was able to use its Thermal Comfort Index modelling to demonstrate that staff working within defined proximity to each heater would maintain comfortable regardless of temporary temperature drops from open shed doors.
Client Feedback
The feedback from both TfL and Vital Energi has been hugely positive. Comfort levels are being satisfactorily achieved, the Advantage and Vulcan heaters delivering effective, consistent warmth for staff in an energy-efficient and sustainable manner.
“We found Herschel and InterLED, who had the provision of these assets…. which aren’t affected by the air. So it was a bit of a no brainer really, for us, and a massive success to get them to where they are now. Already, our staff wellbeing is incredibly high and people are very, very happy with them.
Within this depot, it’s 24/7. We only shut on Christmas Day. So getting this kit in into the right place in the least disruptive way as possible is an absolute requirement for us at TFL, and I’m happy to say that we’ve delivered that here”.
James Merci, TfL Project Manager“We needed to find a solution that heated people rather than spaces. And the IR heaters that were proposed by our engineers originally was deemed to be the most sensible option…and that’s proved the case.
We’ve engaged with InterLED and you’ve taken that concept and delivered this which has proved to be fantastic. All the feedback has been remarkable really, and the install is really neat/tidy. The team have been really professional”.
James Asterley, Vital Energi Ops Manager
A Model for Zero Carbon Heating in Large Operational Sites
Large industrial and commercial buildings, including transport depots, have always been difficult to heat sustainably and efficiently. High ceilings, open bays, constant vehicle movement and frequent draughts often leave traditional convection-based systems ineffective, as warm air escapes before it can provide meaningful comfort.
Infrared heating addresses these challenges by directly warming people, surfaces, and objects rather than attempting to heat the surrounding air. Infrared is an ideal replacement for gas-powered systems offering targeted comfort, reduced heat loss, and significant carbon-saving potential.
Mick Baines, MD InterLED comments:
“From the outset, this project was recognised as a challenging environment for electric heating. We were fully confident however that, with the right approach, it could be successfully delivered through infrared. Vital’s technical team took on board all our guidance, working carefully within the parameters set by TfL, to develop an effective and robust design.
Clear, evidence backed discussions around thermal comfort, supported by heat mapping, provided full assurance on achievable ambient temperatures relative to external conditions.
The resulting system, with flexible, easy to use control, enables staff to maintain consistently high levels of comfort. We are thrilled that the success of this project has led to further projects within the TfL estate”.
The successful deployment of an infrared heating and controls system at the Therapia Lane tram depot demonstrates the viability of electrified infrared technology for decarbonising hard to heat spaces. With measurable improvements in comfort, operational flexibility, and carbon reduction potential, the project provides a scalable model for other industrial and transport facilities across the UK. Infrared systems have additional benefits of very low maintenance, no single point of failure and can be implemented in stages.
Paul Morey, CEO Herschel Infrared, outlines:
“This was our first large-scale commercial installation since InterLED became part of the Herschel Infrared Group. Our ability to now offer the full heating system service from design and manufacture to installation has proved to be a great success on this project. TfL have extremely high standards, and the results are fantastic evidence of what we are able to deliver for similar organisations seeking to decarbonise their heating”.
Contact our team for further information on this project and for advice on decarbonising hard to heat buildings with infrared heating.
