Viewing archives for

Renewed Lamps for Old: The Circular Economy is business as usual for heritage lighting

In May 2023, the SLL held a well-attended CPD at Coco Lighting in Essex, giving members a practical look at how light fittings can be re-engineered to TM66 Circular Economy principles, rather than scrapped. One striking example on the bench was a 2m diameter cylindrical opal diffuser, one of several feature lights from the atrium of a large office. Formerly populated with T5 fluorescent lamps, transformation was underway to replace these with bespoke LED linear modules. It wasn’t straightforward; our hosts explained the positions for the T5 lamps had been carefully defined to ensure a uniform wash around the sides and face of the cylinder. An LED source is very different to a fluorescent tube, posing a particular challenge where an omnidirectional light spread is wanted. The proposed solution had to be engineered to ensure the desired effect was achieved.

As we stood around the bench looking at this huge piece of engineering, it seemed not only obvious it should be refurbished, but perverse that it might not have been. The quality of the original fitting stood out. After many years of use, the diffuser material showed no signs of heat or UV damage. The client had no desire to change the lighting or aesthetics of the entrance. If you were to scrap it, something new would be needed, to fit just the right space on the ceiling, not require new structural support behind, and give a similar light level. The original lighting was just right for the space, and now benefits from a much-reduced energy bill and no need for difficult lamp changes.

Whilst a late 20th Century office is unlikely to be considered a heritage building, it may become one in time if it is good enough. What stands out with historic buildings is often the quality of the original build. And this often includes ironmongery, furniture, and the lighting.

Ely Cathedral dominates the skyline of the Fens, and later this century will celebrate 1000 years existence. It remains serving its purpose as a place of worship, yet just like our T5 lighting diffusers needs updating and repair from time to time, to ensure it best meets the demands of our world today. Gas lighting was installed in the mid-19th Century, lasting through to the 1930s[1]. Little remains of the scheme, other than two huge gasoliers, standing either side of the High Altar. First converted to electric lighting in the 1930s scheme, these fittings have seen several alterations to their light sources in the past. They are now being upgraded from tungsten capsule lamps to miniature LEDs in the workshops of Great British Lighting, as part of the current scheme to re-light the cathedral.

TM66 has a good checklist in Section 9.4 for use when looking at the re-manufacture of light fittings. When considering refitting a historic light fixture, heritage conservation principles then also need to be applied. Or in medical terminology, “first, do no harm”. We have to pose the following further questions:

  1. What is wrong with retaining the status quo?
  2. What is the objective of the renewing the fitting? Is it electrically unsafe, too bright, too dim, hard to maintain?
  3. Is it technically achievable, at an economic cost?
  4. What are the risks of transporting it off site? Could it be worked on in-situ instead?
  5. Is the intention to replicate the current lighting effect, or do something different?
  6. Will the refurbished fitting retain sufficient original character? New technology may offer energy efficiency, but so too would adding double glazing to stained glass windows.
  7. Could new technology introduce new risks to the building, say through the heat from drivers where there previously were none?
  8. If a previous intrusive modification has disrupted the original design, can it be re-used, minimising the need for further such modifications?
  9. What consents will be needed for any modifications?
  10. If the fitting is not re-used, what will happen to it? Few clients will want a relic non-functional light fitting on display.

When considering an old light fixture, what are we trying to replicate? If it once had gas mantles, the light would have been a slightly different colour tone, perhaps at odds with modern expectations. Glass diffusers with GLS lamps in would usually have intensity hot-spots close to the bulbs. Does one replicate this with LEDs or go for a uniform wash? Imperfections can make for charm.

Historic England offers some guidance here[2]. Many early electric light fittings were adaptations of gas fixtures, with pipes used for wiring right back through the building. Lighting designers in the 1930s lacked precedent for how to make use of this new technology. One early innovation was just to invert the arms of chandeliers for better light distribution, since an upward burning flame no longer needed to be accommodated. So a degree of adaptation of the fitting can be justifiable in a historic context, to get the best result from the technology.

Back to the Ely gasoliers. Once the principle of re-use was agreed, the next step was to have them carefully dismantled and transported for refurbishment. Here, detailed record-keeping by the Cathedral Archivist was invaluable, with photos on file of the previous disassembly for transport and refurbishment undertaken for the 1990s scheme. Once stripped down and cleaned, a design could be developed to integrate new light sources. Following the principles of previous adaptations, rather than place lights on the old gas spigots themselves, small LED capsules, using magnetic fixings, will be placed around the circular band beneath, to illuminate glass crystals fixed onto the gas outlets in the past. At present the work is underway and the gasoliers will be ready to return to the Cathedral later this year.

Heritage projects come in all sizes and budgets. Retaining elements of lighting can be a cost-effective way to keep character. The Norris Museum in St Ives, Cambridgeshire, was one such example. Totally inadequate for the museum, rows of small glass shade pendant lights hung above dark wooden display cases bathed also in uncontrolled daylight. Nevertheless, it had a quaint charm. Following a successful Heritage Lottery Bid, a full refurbishment was carried out, with new and far superior lighting installed. But we found a home for a few of the salvaged glass pendants, lighting the replica study of the museum’s founder Herbert Norris.

We picture working with traditional materials such as wood and metal when thinking of worthy historic light fixtures. But what if the building is from the mid-20th Century and the material palette includes concrete and asbestos? This was the challenge presented at Grade II* Listed Guildford Cathedral, an interwar design completed in 1965. Light fittings, along with most of the interior surfaces were finished with an asbestos coating but integral to the appearance of the space. So following careful consideration, the wall sconces, pendants and external bulkheads were removed from site by appropriate licensed contractors and stripped of asbestos. Only then could they be properly examined and disassembled, and their refurbishment planned.

In looking back at these examples, we can see that re-engineering of light fittings is nothing new, and that quality design of a product generally leaves us with something worth saving. TM66 provides a poignant new emphasis on this, with a focus on the embodied carbon and other climate costs associated with constantly manufacturing from fresh raw materials. By some estimates World copper reserves could run out within the next 30 years[3]. As for the medieval villagers pulling down redundant castles to use the stones for their houses, it will soon simply be too extravagant to use new metal where existing is readily to hand.

But is it enough? As TM66 recognises, daylight is our most efficient light source. For the first 800 years of its existence, beyond its glorious windows Ely Cathedral had just a few candles or pitch-torches, and these would have only been for task lighting. Even the 1930s electric scheme sought only to light specific areas, emphasising the lighting of people and not the building. Yet as slimmer profile light fittings and other technology have become available, there is a temptation to light every last niche and archway, far beyond what could have been imagined for the original build. For meaningful energy savings, we must not slash the consumption of converted halogen fixtures only to treble the amount of new lighting in the building. Just as the extensive outdoor lighting schemes of the past decades are being critically re-appraised now for their effect on the night sky and ecology, so too indoor schemes must be carefully considered in terms of what we are lighting, and why. We should recognise there can be beauty in darkness and what we choose not to light too.

[1] A brief history of artificial lighting at Ely Cathedral (

[2] Internal Lighting in Historic Buildings | Historic England

[3] TM66 Section 9.3


To view the full published article online, please visit SLL Light Lines Magazine

Greening our Heritage Properties: a holistic approach to energy efficiency

Author: Chris Hughes, Principal Engineer & Engineers Without Borders UK Change Maker

England has one of the oldest building stocks in Europe. Around 20% of our housing was built more than 100 years ago. In addition, we have many other valued period properties, from palaces and stately homes to the halls of power in Westminster and Whitehall. The need to regenerate these structures to be more energy efficient is unavoidable – and it is vital that engineers take a sympathetic look at the solutions available.

In its sixth Carbon Budget, the Committee for Climate Change stated that buildings, including homes, are the 3rd largest carbon emissions producers in the UK – accounting for 13% of all the UK’s carbon emissions. We can’t drastically modify these heritage structures, and for more modern buildings it is neither feasible nor environmentally desirable to conduct a mass demolition and rebuilding programme, so we need to find practical ways to decarbonise our existing and historic building stock. The National Trust has already assessed its carbon outputs and has set ambitious targets to decarbonise by 2030 – but how can engineers balance issues of sustainability and energy efficiency against the need to preserve original structural features and fabrics?

It cannot be assumed that modern or ‘standard’ engineering and technologies will solve all these problems. Adapting heritage sites to meet modern usage and environmental demands requires an appreciation and understanding of the building’s structure, the environment in which it sits, and the solutions that sustained it in the past. For example, visitors to heritage attractions expect modern facilities which need to be incorporated sensitively. The historic building itself may have been designed as a family home originally, but now it will have back offices for staff, storage requiring precise humidity conditions for precious artifacts, and sometimes private accommodation for the incumbent owners. This means multiple requirements regarding heat, light and ventilation that need to be met sustainably and efficiently.

These conflicting demands do not just apply to stately homes, of course: many public buildings including hospitals, town halls, theatres and schools face similar challenges. In addition, large swathes of our basic housing stock comprise Victorian terraces, 1930s suburbs, post-war ‘homes for heroes’ and garden cities. As engineers, we need to find solutions that will not just deliver short-term energy bill savings, but that transform these aging buildings into sustainable living spaces.

Indigenous or vernacular design, which uses readily available material resources, hints at some solutions, as well as ‘lost’ building practices. Shutters can help keep heat in at night, natural flooring materials can retain heat but remain permeable, and reinstating ‘cold’ roofs allow the removal of humidity and reduces thermal losses from insulating at ceiling level. We can draw inspiration not only from the UK, but internationally. In Ghana, locally available wood and stone are variously used to combat atmospheric conditions ranging from dry heat to extreme humidity.  In north Africa and the Gulf peninsula wind towers provide a means of passive cooling using the prevailing wind direction. Malay houses are perfectly adapted to the high humidity with natural materials promoting ventilation and providing solar shading with overhanging roofs.

In the UK, we are relearning the benefits of some older materials. Concrete render applied in the mid-20th century to reduce heat loss is now causing damp problems in properties originally constructed of porous materials that easily exchange moisture with the air. These concrete skins are now being replaced with traditional lime renders, which will work sympathetically with the building’s original structure. Sustainable, natural wool insulation is being reintroduced. Sash windows are common in heritage structures, and need regular maintenance due to their timber frames, but keeping on top of this can reduce cold draughts.. Repairing external walls can also reduce uncontrolled infiltration.

The potential to improve energy efficiency and decarbonise our housing stock is significant. Thousands of houses were built in the same period using similar construction techniques and materials, which means they are likely to face the same issues. But this also means that appropriate, sustainable solutions can be applied on a grand scale (if the industry can respond to demand).

It further offers the opportunity for householders to come together collaboratively and collectively. For example, it could give them better buying power to reduce the cost of investment, or the ability to pool their own skills to help each other achieve the necessary improvements. And in the end, being invested in the process is what will make the difference in achieving our carbon reduction targets, reversing climate change, and securing the long-term future of the planet.

Clearly, what is required is a holistic approach that considers the existing building fabric and design, the needs of the occupants over time and the longer-term impacts of any energy efficiency measures. It is simply ineffective and inefficient to disregard solutions that have been deployed in the past – especially if they were designed into the structure and use of the building. In taking this approach to regeneration, we can preserve our past whilst protecting our future. This is precisely the philosophy that underpins Engineers Without Borders UK and the principles of global responsibility that it promotes.

Become part of our global movement today at

Article published in E&T IET magazine and accessible online:

An exciting new chapter for CBG Consultants & Light Perceptions!

We are excited to announce that we have established a new lighting consultancy division with the acquisition of Light Perceptions Ltd, providers of specialist lighting design services for more than 20 years. Light Perceptions’ experience covers landmark ecclesiastical and historic sites, private estates, museums and galleries, and other public buildings. Bruce Kirk, Founder of Light Perceptions, has joined the CBG Board.


CBG’s Managing Director Andy Payne said: “Through the CBG Light Perceptions division, we will be able to offer bespoke lighting design and project management services. This is fantastic news for our whole team, for our clients, and for others we collaborate with.”


Director Bruce Kirk added: “With a growing focus on sustainability in all stages of the construction lifecycle, the combination of Light Perceptions’ expertise and CBG’s resources means we can offer in-house, a comprehensive low carbon managed lighting and MEP solution across all projects.”


We look forward to this new era and the opportunities it will bring for our clients, employees, and everyone we work with.


For more information, please contact us.



CBG Project features in Architects’ Journal

St Paul’s Cathedral School is a co-educational preparatory school for boys and girls aged 4 to 13 and a residential choir school for the boy choristers of St Paul’s Cathedral.
The school identified a need to increase capacity and improve its facilities to its pupils. The project included building a new boarding house, which was to provide accommodation to reflect current regulations, with the desire to exceed the expectations and to secure the culturally significant English Choral tradition for future generations.

CBG Consultants was appointed to provide M&E design and sustainable consultancy services for the project. The CLT extension provided a good opportunity to reduce energy costs through high insulation and low infiltration rates inherent with the timber panel building system. The building was modelled to test overheating and the detailed design incorporated feedback from the modelling including optimising glazing selection and variable ventilation rates within the spaces to mitigate both occupancy numbers and summer overheating.

For more information about the project, please read the article on Architects’ Journal.

CBG Project Features in Architects’ Journal

CBG Consultants were appointed to provide M&E Consultancy Services on a new scheme for Dacorum Borough Council. The scheme looks to redevelop the Paradise Depot site to provide affordable housing which will consist of a new apartment block of 56 one and two-bedroom homes and the site will include cycle and scooter storage and a residents’ garden.

The homeless charity DENS currently resides at the Paradise Depot site and plans are also to include rehousing the charity into a brand new two story building.

The Paradise Depot scheme is part of the council’s target to build 350 homes by 2026.

For more information about the project, please read the article on Architects’ Journal.


CBG Consultants are back on site!

As we begin to see lockdown restrictions start to ease across the country, at CBG Consultants we have gradually started to return to site. All of our engineers have received additional PPE and health & safety guidelines to maintain social distancing.

Pictured is a great example of how we are embracing the ‘new’ normal, a site meeting set up in the beautiful grounds of a private residential property in Wiltshire (we wish that all of our site visits were like this!).


More Awards for The Stokes Centre for Urology, Royal Surrey County Hospital

We are proud to announce that The Stokes Centre for Urology has won the RICS South East Social Impact Awards 2020 in the categories of Healthcare and Project of the Year.

Working closely with K2 Consultancy Limited, CBG were appointed as M&E consultants for the project to prepare M&E performance design, thermal modelling and Part compliance services and to carry on client side providing technical advice and checking of contractor design.

Image courtesy of ADP


International Women in Engineering Day 2020

International Women in Engineering Day (INWED) now in its seventh year, was launched to celebrate women in engineering around the world. To raise awareness of INWED we asked our women engineers to share their stories in relation to this year’s theme of ‘Shape The World’.

Maria Hurtado, Electrical Engineer

“When I first realised the impact that our day-to-day life can have on our environment, I wondered how this was being solved and whether I could be part of the solution. Why couldn’t I? After 4 years at university and over 3 years of experience within the building services field, I am only at the beginning of my career but I can say that I am making my own small contribution towards a better world. Fortunately, most projects nowadays are focused on reducing their carbon footprint due to an increased environmental awareness, and I can be part of them as an engineer. As a quick example, I have participated in the electrical design of a new boathouse at Shiplake College, a sustainable BREEAM certified building, that was recently completed.”

Lindsey Arnott, Senior Sustainability Engineer

“I grew up in a house built in 1970. It was an unusual design with a large surface area to volume ratio. As such it was really hard to keep warm. Not wanting to waste energy we developed a daily ‘radiator routine’ of adjusting the TRVs: before you go to bed you turn down the living room radiators and turn up the kitchen one ready for the morning. Before you go to work/school, turn down kitchen and turn up the living room. And at some point in the evening remember to turn up the bedroom radiators. But good design for energy efficiency and comfort should be nearly invisible. It shouldn’t have to rely on the behaviour of occupants. After experiencing poor design and learning about the causes and consequences of climate change, I wanted a career where I can help shape the world. As a Sustainability Engineer I get to be part of a team designing low carbon buildings, creating healthy environments in schools and workspaces, and making homes comfortable and efficient to run. I love my job and get a lot of satisfaction from seeing the impact I can have.”

Anna Szot, Lighting Designer

“My passion for design started from a very early age. My interest in design was spread over many disciplines from spatial and interior design to product design. I was interested how our natural surroundings and built environment influence our life. However, my journey with lighting begun later when I have joined CBG and realised that light is a single unifying force that can bring everything together. I have been fascinated by the power of light to transform a space; enhance the way we perceive architecture and world around. This realisation had put me on the lighting design path.

By using LED tunable technology and modern lighting controlling solution we can create emotions and interactions with the world that can make difference to the way we live. Electrical power consumption for lighting is one of the largest sources of building energy consumption therefore Daylighting is a cornerstone strategy aiming at reducing a building’s energy consumption. Daylight responsive dimming significantly reduces lighting energy use. Well design lighting is very important as Light creates not only a visual interest and specific spatial atmosphere; it also has biological and psychological effects that can impact our health and wellbeing. It is all about balance and harmony. Balance of light & shadow, to create harmony and well-being in all aspects of everyday life.

I am hugely encouraged by the growth of the number of women that are nowadays more and more involved in the lighting industry.”

#INWED20   #ShapeTheWorld




Award Winning Project – Fordham Abbey Dojima Sake Brewery

We are proud to announce that Fordham Abbey Dojima Sake Brewery has won the RICS East Social Impact Awards 2020 in the Leisure category.

The Dojima Sake Brewery has been brought to the UK within the historic grounds of Fordham Abbey in Ely Cambridge. Working closely with architects SCABAL and Kay Pilsbury Thomas, CBG were appointed as M&E consultants for the project which included the building environmental design, process and production services and the major infrastructure upgrades to the site.

More Awards for Dorothy Goodman Special Needs School

We are proud to announce that Dorothy Goodman Special Needs School has won the RICS East Midlands Social Impact Awards 2020 in the categories of Education and Project of the Year.

Working with Grayling Thomas Architects this award winning project has created a sensitive, purposeful and stimulating learning environment which meets the needs of pupils, from 11-16 years, with a whole spectrum of learning difficulties.