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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:

Pride Month – Behind the flag

In June 1969 a gay bar in Manhattan, called the Stonewall Inn, was raided by police. Riots followed for days in protest of discrimination and police brutality, sparking the gay rights movement in the US. This movement spread across the world, adopting the term Pride, and is celebrated across the month of June as the anniversary of the riots.


The pride flag was created by Gilbert Baker in 1978 to represent the LGBTQ+ community and refused to trademark it. There have been many iterations, including removal of colours and addition of new patterns to represent the unique struggle of BAME, transgender, non-binary and intersex people. Originally it was seen as controversial for use by companies and public bodies, now it is common place across the month of June.


Despite the legal strides, most significantly the Gender Recognition Act 2004 and the Equalities Act 2010, there are still cultural barriers to inclusion.

Here at CBG we want to support breaking down barriers and champion inclusivity.

Day in the life of a Graduate at CBG Consultants


From a young age I’ve always been interested in making things and developed a curiosity for how things work, so a career path as an engineer was a natural progression for me.



There were several of reasons, but the biggest attraction was the vast portfolio of projects CBG are involved with.



Very insightful, I have learned a lot from colleagues. Having the opportunity to be hands on with the work means I’m learning a great deal as I go.



I usually start my day by catching up with lead managers of the projects I have been appointed to. Then depending on the stage of the projects, I’ll be designing mechanical systems from scratch including calculations and sourcing. Some days involve site visits for surveys to get a better understanding of projects or I’ll have on site meetings to attend.



There are some aspects of Uni I have found to be very useful, especially CAD standards and report writing.



The diversity of projects I get to work with, ranging from hospitals, banks, data centres, residential, rail etc. Mentmore Towers was particularly memorable, as it was interesting to see such a historical and iconic building.



Conforming to deadlines and finding solutions to complex mechanical problems.



I’ve completed a 2 day Advanced Revit training, and I’ve had the opportunity to attend weekly CPDs. The mentoring and guidance from superiors and peers is ongoing and everyone has been really supportive.



Great, my co-workers are friendly and everyone works hard. There is a good balance of work Activity Days and team meals.  We will also sometimes attend post work events together, and there has been the opportunity for people to take part in competitions like the annual SLL Ready Steady Light competition



I aspire to reach Chartership status, which CBG will assist me with. As well as giving me access to memberships such as IMechE.



Absorb as much information as possible no matter what discipline and ask as many questions as you can.



In2science UK CBG Workshop – starting a career in STEM

We are working in partnership with the charity In2science UK. Due to poverty and social background being huge obstacles for young people to obtain a career within the STEM industry, the charity sets out to help overcome these barriers. Working with industry professionals, In2science UK provides young people from low-income and disadvantaged backgrounds an opportunity to gain practical insight, knowledge, and confidence. Students work alongside and attend workshops hosted by industry professionals.

We have set up a workshop and present to a group of 16-18 year old students who are interested in starting a career within STEM.

The structure we lay out for our In2science UK workshops are as follows:

Key questions we get asked from students are:

Try to attend a summer vocational placement to make contacts and understand whether you enjoy the industry. Microsoft Excel is a very useful tool for calculations and efficiently analysing data, so we recommend that students obtain a good knowledge on its abilities.

The Khan Academy has numerous free online tutorials on various STEM subjects.

New regulations (June 2022) have just been put into place and as a company, we are trying to learn how they will affect our future designs. In 2025 the ‘Future Homes Standard’ will be released, and this will change how we design domestic buildings.


The feedback that we have received from attendees after our workshops:

For information on how you can volunteer for In2scienceUK and inspire a young person into STEM click here

Phasing Out the Installation of Fossil Fuel Heating in Homes

The government has released a consultation on the phasing out of fossil fuel heating in homes off the gas grid.

This consultation sets out proposals to phase out the installation of high carbon fossil fuel heating systems in homes, as committed to in the 2017 Clean Growth Strategy.

Here are some of the key proposals for the sector from the report

This consultation was launched alongside the Heat and Buildings strategy.

The government is looking for responses from the heating industry, consumers and those with a wider interest in the UK’s net zero ambition to help shape the design of the policy. Please feel free to provide your response to the consultation questions here. The closing date for the consultation is 12th January 2022.

Please contact our sustainability team if you need any assistance to understand low carbon heating options. We offer a wide range of services including carbon appraisals and Low and Zero Carbon feasibility studies where we can provide advice early on in the design.

Earth Day 2021

Net-Zero is an ambitious target for governments, companies and institutions to dramatically reduce environmental impact and to prevent the most damaging effects of climate change. Significant cuts in emissions across the built environment are required in achieving this goal.

At CBG Consultants Ltd, we create buildings that minimise their environmental impact. We have a wealth of experience in thermal modelling which enables us to understand the performance of a building through a computer-generated model to assess energy consumption and carbon emissions.

Understanding how buildings generates carbon emissions and the predicted impacts of various measures and strategies through detailed modelling will generate a robust route map to Net Zero Carbon.

Remember, it’s up to us all to fix this climate crisis. Take your first step by visiting WWF’s carbon calculator to understand your carbon footprint and take actions.

The New London Plan 2021

After more than three years in the consultation process, the New London Plan came into force on 2nd March 2021.

The Plan sets the overarching framework for how London will develop over the next 20-25 years. It gives focus on new developments and redevelopments to meet low carbon, energy efficiency and sustainability standards as part of a drive to make London a zero-carbon city by 2050.

For further information, please visit ‘The London Plan 2021’

Our team have extensive experience supporting projects through the planning process on major London schemes and advising on the policy requirements. We can provide a full range of MEP and sustainability services in all areas of the built environment.

For information on the adopted changes and how they may affect your project, please get in touch!

© Greater London Authority


UK Climate Change Committee – Sixth Carbon Budget

Last week the UK Climate Change Committee (CCC) published their recommended Sixth Carbon Budget as part of the UK’s path to net zero carbon by 2050.

The advice is a reduction in UK greenhouse gas emissions of 78% by 2035 relative to 1990. This would achieve well over half of the emissions reduction required by 2050 in the next 15 years. The analysis in the report shows this is feasible, provided effective policies are introduced across the economy without delay. The budget requires a major investment programme, worth around £50 billion each year from 2030 to 2050. However, the CCC estimates net costs of meeting the budget to be low, equivalent to less than 1% of GDP.

The report covers every section of the economy including buildings. Specific actions for the buildings sector include:

To make all buildings energy efficient and ultimately low-carbon a clear timetable for policy standards is needed along with industry changes to rapidly scale up supply chains for heat pumps and to develop the option of hydrogen for heat.

CBG applies these principles with a ‘fabric first’ approach to reduce energy demands by focusing on passive design. Then it is followed by the design of efficient buildings services.

We keep up to date with all building regulations and policy guidance and can provide CPD presentations to assist with the transition to low and zero-carbon buildings. Please do contact us to schedule a CPD for your team.

Minimum Energy Efficiency Standard (MEES)

The Minimum Energy Efficiency Standard (MEES) came into force in England and Wales in April 2018, these standards apply to private rented residential and non-domestic properties.

The aim of the MEES is to encourage landlords and property owners to improve the energy efficiency of their properties by upgrading fabric, installing new boilers and energy efficient lighting etc.

Properties with EPC ratings of E or less will be subject to restriction on the granting and continuation of the existing tenancies .

Domestic Property

Minimum Energy Efficiency Standards (MEES) applies to any privately rented property which are legally required to have Energy Performance Certificate (EPC), these include assured short hold, regulated and domestic agricultural tenancies. From April 2018, landlords will not be able to grant a tenancy to new or existing tenants with an EPC rating of F and G and from 1 April 2020, they’ll not be able to continue letting the property without improvements.

Landlords are not expected to finance the cost of improvements but to use third party resources such as Green Deal and Local authority improvement grants. Exemption can be claimed where they are not able to get the funding/grant to cover the cost of the improvements, or are not able to achieve the minimum EPC rating (E) even after improvements. Any exemption must be registered on the RPS Exemption Register.

Non-Domestic Private Rented Property

Similarly, as above from 1 April 2018, non domestic landlords must not grant new tenancies without the minimum energy efficiency standards. They cannot continue to let the property after 1 April 2023 where property has an EPC rating of below E.

All the improvements to Non-Domestic properties will be funded by landlord or tenant, there is no third-party funding available. Landlords may be able to claim exemption, all exemptions must be registered on the RPS Exemption Register.

We have a team of Qualified Level 3, 4 and 5 Energy Assessors, who can provide assistance with MEES compliance and provide advise on how to achieve MEES compliant building. Please do contact us should you wish to find out more.