Embodied carbon and circularity of luminaires

At a glance

From CIBSE's own listings and two CIBSE Journal articles (2022 and 2023), read 7 November 2026. TM65.2 and TM66 themselves are paid documents and were not read.

TM65, TM65.2, TM66 and EPDs: what each one is

Four documents get mixed up when a client asks for “the carbon figure” for a chandelier or a pendant. They answer different questions, and a decorative or bespoke luminaire may have none of them. Knowing which is which lets you ask a precise question and read the answer for what it is.

The studio does not hold carbon or circularity data for any luminaire, and this sheet gives none. It tells you what to ask a supplier or partner workshop to provide.

Reading the numbers without being misled

An estimate is not a declaration. TM65 and TM65.2 give a conservative estimate from a materials list. An EPD is a verified statement to a rule set. Do not set one against the other as if they were the same kind of number; ask which method each figure comes from, who calculated it, and what it covers. The CIBSE Journal’s 2023 article on TM65.2 says it is not meant to replicate or replace a full life cycle assessment, though its results are closer to one than TM65’s generic data.

Known limits of the method. CIBSE’s TM65 page lists some: the recycled-content input does not currently affect the calculation, some materials (zinc alloy, for example) are missing from the database and the closest material is substituted and noted, the default factors come from a database that is being replaced, and replacement assumptions default to 10 per cent if left blank. The CIBSE Journal article on TM65.2 says aluminium has separate coefficients for 100 per cent recycled and 100 per cent virgin material. We have not read TM65.2 itself, so ask the supplier which version of the tool and which coefficients were used.

Carbon and circularity are different questions. The CIBSE Journal’s module says low embodied carbon does not guarantee circularity, and a circular product is not automatically low-carbon, although the two are linked. It also warns that manufacturers may greenwash products, so claims need checking, and that LED life depends heavily on design quality, heat management and driver electronics. Integrated LED units usually have to be replaced whole when one component fails, which limits reuse.

A bespoke piece may have no data at all. A one-off made for a project is unlikely to have an EPD of its own (see how to read an EPD). That is not a reason to skip the question. A materials list with masses, a stated method and honest gaps are worth more than a single figure with no basis.

Where carbon and circularity sit in a decorative luminaire

These are the places where a decorative luminaire’s carbon and circularity are decided. They are a guide to what to ask, not a ranking: we hold no figures to order them, and the weight of each depends on the design. The first five rows follow the inputs CIBSE lists for TM65 (materials, manufacturing, sourcing, transport, service life and replacement).

Ten questions for the supplier

Ask for these in writing from the partner workshop or the luminaire supplier, before tender return. Answers can be “not available”; the aim is to know which.

1. Materials list. Each material and its mass, for the frame, glass, light source, driver, fixings and finish.
2. Metals. Alloy, recycled content and the evidence for it, and where the metal was sourced.
3. The carbon figure, if any. Is it a TM65.2 estimate or an EPD? Who calculated it, which version of the tool, what boundary and what service life were assumed?
4. Made and shipped. Where each major part is made and how it travels.
5. Replaceable parts. Can the light source and driver be replaced without damaging the fitting, with common tools? Is the product designed for the parts most likely to fail to be reached easily? (CIBSE Journal, 2022.)
6. Spares and records. What spares are held, for how long, and is there a unique identifier on the product (such as a QR code or tag) that links to drawings and spare sources? (CIBSE Journal, 2022.)
7. Repair and refinish. Written repair instructions; whether the finish can be renewed rather than the part replaced.
8. Take-back. Is there a route to return a fitting for refurbishment, reuse or recovery at end of use?
9. Circularity score. Has the product been assessed with CEAM-Make or CEAM-Specify? By whom, and has anyone independent checked it?
10. Packaging. What it is, whether it is reusable, and who takes it away.

The questions are also the content of the operation and maintenance file. The O&M information sheet covers what that file contains; the sustainability documents sheet covers the wider paperwork a tender asks for.

Tenderer to provide for each luminaire type [reference]: a materials list by mass; alloy and recycled content of metals with evidence; the embodied carbon figure if available, stating the method (CIBSE TM65.2 estimate or EPD), the person who calculated it, the version of the method, the boundary and the service life assumed; and where each major part is made.

Tenderer to state whether the light source and driver are replaceable with commonly available tools without damaging the fitting; what spares are held and for how long; whether repair instructions and a unique product identifier are provided; and the route for return, refurbishment or recovery at end of use. Where the product has been assessed with CEAM-Make or CEAM-Specify, state the rating, who carried it out and whether it has been independently checked.

Any statement of recycled content, low carbon or circularity to be supported by documents. Where no data exist, the tenderer is to say so; an estimate is not to be described as a verified declaration.

Standards and sources

• CIBSE TM65.2: Embodied carbon in building services: lighting (July 2023): CIBSE listing read; document not read.
• CIBSE TM66: Creating a circular economy in the lighting industry (October 2021) and CEAM tools: summary only; not read.
• CIBSE Journal: TM65 and TM66 CPD (September 2022); TM65.2 (August 2023): trade press; read in full.
• BS EN 15804:2012+A2:2019 (EPD core rules for construction products): BSI Knowledge, via search summary: Current, Under Review. Not read.

Questions we are asked

What is the difference between TM65.2 and an EPD?

TM65.2 is a CIBSE method that produces a conservative estimate of a luminaire's embodied carbon from its materials and processes. An EPD is a verified declaration of life-cycle impacts to a stated standard. CIBSE says TM65.2 does not aim to replace EPDs. Do not compare the two figures as if they were the same kind of number.

What does TM66 measure?

How circular a luminaire is: whether it can be repaired, upgraded and recovered. It does not calculate carbon. CIBSE published it in October 2021 with two tools, CEAM-Make for manufacturers and CEAM-Specify, a quicker comparison for specifiers.

Does a bespoke chandelier have an EPD?

Probably not. An EPD usually describes a defined product made repeatedly, and a one-off piece made for a project is unlikely to have one of its own. Ask instead for a materials list, a stated method and honest gaps, as the question list suggests.

Can the studio give me a carbon figure for a luminaire?

No. The studio holds no carbon or circularity data for any luminaire. It can ask the partner workshop to provide the information in the question list, and tell you what they say.

Is a low-carbon luminaire also circular?

Not necessarily. The CIBSE Journal's module says low embodied carbon does not guarantee circularity, and a circular product is not automatically low-carbon, though the two are linked.

What should the specification say?

Ask for a materials list, the method and boundary of any carbon figure, recycled content evidence, replaceability of the light source and driver, spares and take-back, and say that an estimate is not to be described as a verified declaration. See the paste-in wording.