Early-Stage Sustainability – Critical Reflection Framework

Sustainability in engineering is often described using the triple bottom line (TBL): environmental quality, social responsibility, and economic viability. A sustainable design should avoid shifting problems from one dimension to another (for example, lower cost but much higher pollution) and should consider impacts not only today but over the full life of the system.

Triple Bottom Line – Environmental, Social, and Economic Dimensions

A simple visual representation of the three interconnected dimensions of sustainability. These dimensions are explored in Steps 2–4 and brought together again in Step 5.

This framework assesses sustainability through five short steps. Each step uses brief reflective questions to guide early-stage reasoning.

• 1. Map the system: define what the design is and how it works across its life cycle.
• 2. Environmental reflection: identify likely hotspots and circularity opportunities.
• 3. Social reflection: consider who is affected and which values or needs matter.
• 4. Economic reflection: explore costs, viability, and supply-chain conditions.
• 5. Integrate & reflect: bring insights together and highlight key trade-offs.

This first step builds a clear picture of what the design is, what it does, and how it exists over time. Understanding the system at this basic level makes it easier to explore sustainability in later steps.

1.1 Define the System

This part clarifies what the design is and what purpose it serves.

• What are you analysing? Describe it in one or two simple sentences.
• What function does it provide? What problem does it solve?
• Who uses or interacts with it? List the main groups.
• Where does it operate? A room, building, city, or digital space?

1.2 Life-Cycle Stages

Every system has a journey from beginning to end. A simple life-cycle outline helps identify where impacts might occur later.

• Materials: What it is made from and where materials come from.
• Manufacturing: How it is produced or assembled.
• Transport: How it reaches its place of use.
• Use: What happens when it is used, and how often.
• Maintenance: What needs repairing or replacing over time.
• End-of-life: What happens when it is no longer needed (reuse, recycling, disposal).

1.3 Baseline & Context

The baseline is the current or most common way the problem is solved. It helps show how the proposed design differs and why it might be needed.

• What is the current solution? Describe how the problem is usually solved today.
• What are its limitations or challenges?What does the current solution not do well?
• Who is affected by the current solution? Users, workers, neighbours, etc.

This step explores where environmental impacts are likely to occur across the life cycle. The focus is on identifying hotspots, material and energy issues, and opportunities for circularity—without requiring detailed calculations.

2.1 Materials & Resource Use

These questions focus on what the system is made from and the implications of material choices.

• What are the main materials used?
• Are any materials scarce, toxic, or highly energy-intensive to produce?
• Does the system depend on critical or politically sensitive materials (e.g., rare earth elements)?
• Are there known environmental or social issues linked to extracting these materials?
• Could recycled, reused, or lower-impact materials replace some of the current choices?
• Is the amount of material proportionate to the function, or is there over-design?

2.2 Energy & Operational Impacts

Many systems create most of their environmental impact during use. These questions help assess that stage.

• Which life-cycle stages require the most energy (manufacturing, transport, use)?
• Does the system consume electricity or fuel regularly?
• Could the same function be provided with less energy?
• Does the system generate emissions, noise, heat, or other pollution during use?
• Could rebound effects occur (e.g., greater use because operation becomes cheaper or easier)?
• Does the design depend on a future cleaner energy mix, or must it perform well under current conditions?

2.3 Waste, Circularity & End-of-Life

Circularity aims to keep materials in use as long as possible and minimise waste. These questions explore how well the system supports circular flows.

• What waste is created during manufacturing or use?
• Are any components being replaced early, before their useful life ends?
• What happens to the system at end-of-life: reuse, remanufacturing, recycling, or disposal?
• Can materials be recovered at high quality, or only downcycled?
• Are components easy to separate and repair?
• Can the system be upgraded without replacing the whole product?
• Does the design encourage long service life (durability, modularity)?
• Could a “product-as-a-service” or leasing model improve reuse or recovery?

2.4 Environmental Hotspots & Assumptions

Hotspots are places where most environmental impact occurs. Identifying them helps set priorities.

• Which one to three life-cycle stages appear most harmful, and why?
• Does the design reduce these impacts compared with the baseline?
• What assumptions support your judgement (energy mix, materials, lifetime, user behaviour)?
• How uncertain are these assumptions, and how might conclusions change if they differ?
• Could scaling the solution (large deployment) create different or larger environmental risks?
• Would a more detailed LCA be needed to check or refine this early-stage reflection?

This step explores how people are affected by the system. It focuses on who benefits, who may be burdened, and whether important human values are supported or overlooked.

3.1 Stakeholder Mapping

These questions help identify everyone who is affected directly or indirectly.

• Who are the direct users of the system?
• Who is indirectly affected (workers, neighbours, maintenance staff, nearby communities)?
• Are there groups easily overlooked (children, older adults, people with disabilities, low-income groups)?
• How does each group interact with the system (user, operator, decision-maker, bystander)?

3.2 Stakeholder Values

Different groups value different things. These questions explore which values matter most.

• What does each stakeholder group value (e.g., safety, ease of use, autonomy, privacy, reliability)?
• Does the design clearly support any of these values? How?
• Does the design risk undermining any values (e.g., dignity, independence, personal data rights)?
• Do some groups' values dominate decision-making? Is this justified?

3.3 Equity, Inclusion & Accessibility

This part examines whether the system creates fair access and avoids excluding or burdening certain groups.

• Who gains the most from this system, and who gains the least?
• Could any group be excluded by cost, language, physical access, digital access, or cultural barriers?
• Does the system consider users with mobility, visual, hearing, or cognitive differences?
• Is the system easy to understand and use without specialised knowledge?
• Does the system increase workload or stress for any group (e.g., staff or operators)?

3.4 Safety, Work Conditions & Wellbeing

These questions explore whether the system affects health, safety, or labour conditions across its life cycle.

• What realistic safety risks exist for users or workers?
• Does the system help people feel safe and in control, or confused and anxious?
• Could failure of the system cause harm? Who would be most affected?
• Do upstream processes (e.g., manufacturing or mining) involve hazardous or unfair working conditions?
• Could simple design or sourcing choices reduce any of these risks?

3.5 Unintended Social Consequences

Social systems often behave in unexpected ways. These questions help anticipate wider effects.

• Could the system change behaviour in unintended ways (e.g., overuse, dependence, new habits)?
• Could digital features increase surveillance, reduce privacy, or create data risks?
• Could the system shift burdens to certain groups (e.g., more work for maintenance staff)?
• Could it change social interactions (more convenience but less personal contact, or new forms of stigma)?
• If the system were used widely, who might be negatively affected over time?

This step explores the economic side of the system: who pays, who benefits, how costs evolve over time, and how stable or risky the supply chains are. Economic sustainability is not only about low cost, but about long-term viability and fairness.

4.1 Cost Distribution

These questions help clarify how costs and benefits are shared across different groups.

• Who pays for the system to be developed or installed?
• Who pays to use or access the service?
• Is the cost manageable for all groups involved, or is it a barrier for some?
• Does the design shift costs from one group to another (e.g., cheaper for providers but more expensive for users)?

4.2 Operating Costs & Lifetime

Economic sustainability depends on how costs behave over time, not just at the start.

• What ongoing costs arise during use (energy, consumables, licences, maintenance)?
• Does the design reduce or increase these ongoing costs compared with the baseline?
• How long is the system expected to last before key components fail or need replacement?
• Is it easy and low-cost to repair, or likely to be discarded early?
• Could early replacement create avoidable economic or environmental waste?

4.3 Supply-Chain & Resource Risks

This part focuses on materials, components, and skills the system depends on — and how stable or politically sensitive those sources are.

• Does the system rely on scarce or difficult-to-substitute materials (e.g., rare earth metals)?
• Are key materials or components sourced from a small number of countries?
• Could political tensions, trade restrictions, or export bans disrupt availability?
• Does the system depend on specialised tools, licences, or expertise that might be hard to access?
• What happens if material, labour, or energy prices rise significantly?
• Could design choices reduce dependence on fragile or politically sensitive supply chains?

4.4 Long-Term Value & Resilience

These questions explore whether the system creates lasting benefits and can adapt to change.

• Does the system deliver long-term value (lower bills, higher reliability, reduced waste)?
• Does it support local skills, jobs, or supply chains?
• Is the design likely to remain useful as technology, policy, or user behaviour evolves?
• Does the overall system appear economically robust or fragile, and why?

This final step brings together the insights from the environmental, social, and economic reflections. The aim is to build a clear overall picture of the design, highlight key trade-offs, and identify areas for improvement.

5.1 Cross-Dimension Summary

These questions help summarise the most important insights across all three dimensions.

• What are the main environmental hotspots you identified?
• What are the most important social issues or value tensions?
• What are the key economic or supply-chain risks?
• Which dimension (environmental, social, or economic) appears most challenging, and why?
• Are there any issues that appear across multiple dimensions?

5.2 Trade-Offs & Value Tensions

Every design involves trade-offs. These questions help make them explicit.

• Are there clear trade-offs (e.g., lower emissions but higher cost, or better access but more material use)?
• Who benefits from these trade-offs, and who may be disadvantaged?
• Are any trade-offs unacceptable from a sustainability or ethical perspective?
• Could small design adjustments reduce or rebalance these trade-offs?

5.3 Design Opportunities & Next Steps

These questions help identify what to do with the insights gathered.

• What two or three concrete changes could improve sustainability across dimensions?
• Which questions remain unanswered because of missing data or uncertainty?
• What information or tools would be helpful in a next phase (e.g., LCA, KPI analysis, policy review)?
• Does the reflection suggest continuing with the design, modifying it, or exploring alternatives?

A university has received repeated feedback from students and teaching staff that many teaching rooms feel dim, visually tiring, and less welcoming than expected. Although the fluorescent luminaires installed across these rooms still function correctly, they no longer provide the visual comfort or atmosphere expected in modern learning spaces. To improve the quality and comfort of teaching environments, Facilities Management is considering upgrading the lighting across all affected rooms.

The following sections apply the five-step sustainability reflection framework to the final solution proposed by Facilities Management. This process serves as an example of how to assess the sustainability of a project and helps identify opportunities that may not have been recognized in earlier stages. There are no right or wrong answers; the framework is intended solely as a tool for critical analysis.

1 Map the System & Context

1.1 System Description

System: The lighting system used in teaching rooms across the university. It operates within indoor learning spaces and is interacted with daily by students, teaching staff, and facilities personnel. Its function is to provide artificial lighting that supports teaching, learning, and prolonged use of these rooms.

1.2 Life-Cycle Overview

To understand where sustainability impacts may occur, the lighting system is considered across its main life-cycle stages.

• Raw materials: metals, plastics, glass, and electronic components.
• Manufacturing: production and assembly of luminaires and control gear.
• Transport: delivery of luminaires and replacement components to campus.
• Use phase: electricity consumption during teaching hours.
• Maintenance: replacement of lamps and control components.
• End-of-life: disposal or recycling of luminaires and lamps.

1.3 Baseline

Baseline: The existing fluorescent lighting system currently installed in the university’s teaching rooms. It operates in the same spaces, serves the same users, and provides the same basic lighting function as the proposed change, but with lower perceived visual comfort and ambience.

This description of the system, its life cycle, and the baseline provides the foundation for the environmental, social, and economic reflections in the steps that follow.

2 Environmental Reflection – Life-Cycle & Circularity

Building on the system, life cycle, and baseline defined in Step 1, this step applies qualitative life-cycle thinking to explore potential environmental impacts. The aim is to identify likely hotspots, material and energy concerns, circularity opportunities, and key assumptions—without requiring detailed calculations.

2.1 Materials & Resource Use

• What are the main materials used?
  The proposed LED upgrade uses electronic drivers, printed circuit boards, aluminium heat sinks, plastic optics/housings, wiring, and packaging. The baseline fluorescent system uses glass tubes, metal housings, electronic ballasts, and small amounts of mercury.
• Are any materials scarce, toxic, or highly energy-intensive to produce?
  Aluminium and electronics are energy-intensive to produce. Fluorescent lamps contain mercury (toxic) and require controlled end-of-life handling. LEDs avoid mercury but increase reliance on electronics and metals.
• Does the system depend on critical or politically sensitive materials (e.g., rare earth elements)?
  Potentially. Some LED phosphors and electronics may involve rare earth elements and globally concentrated supply chains. The level of dependency cannot be confirmed without product specifications.
• Are there known environmental or social issues linked to extracting these materials?
  Yes. Metals and rare earth extraction/processing can involve high energy use, land and water impacts, and potential labour/community harms in mining regions. For the baseline, mercury becomes a health and environmental risk if disposal pathways are weak or poorly implemented.
• Could recycled, reused, or lower-impact materials replace some of the current choices?
  Potentially. Procurement could specify recycled aluminium content, higher recycled-content plastics, and supplier transparency on sourcing. Another possibility is reuse of existing housings where feasible, or retrofit strategies that reduce replacement of whole units. Whether this is possible is unknown at this stage and depends on the existing fittings and technical compatibility.
• Is the amount of material proportionate to the function, or is there over-design?
  Unknown at this stage, and this uncertainty matters. A full replacement programme could create large embodied impacts and costs. Before accepting that burden, the social problem should be evidenced more clearly (e.g., how widespread is discomfort; which rooms; which groups; how severe; how often). If only a small proportion of spaces or users are affected, targeted interventions may deliver the same social benefit with much lower material turnover.

2.2 Energy & Operational Impacts

• Which life-cycle stages require the most energy (manufacturing, transport, use)?
  Likely the use phase (electricity demand over many operating hours), especially under the baseline. Manufacturing becomes more important for LEDs due to electronics and aluminium, and may be significant if existing luminaires are replaced early.
• Does the system consume electricity or fuel regularly?
  Yes. Lighting consumes electricity whenever rooms are occupied and teaching rooms are used frequently, creating cumulative energy demand.
• Could the same function be provided with less energy?
  Yes, and critical reflection requires considering alternatives beyond “replace everything with LEDs”. Options could include: improving cleaning/maintenance of diffusers, re-aiming or re-zoning existing lighting, adding task lighting at critical locations, changing layouts to reduce poorly lit areas, upgrading controls only (timers/occupancy) while retaining fittings, selective replacement of the worst-performing rooms first, or reducing operating hours through better scheduling and automatic shutoff. These alternatives should be considered before committing to a high-material, whole-campus replacement.
• Does the system generate emissions, noise, heat, or other pollution during use?
  Direct on-site emissions are not applicable (electric lighting). Indirect emissions depend on the electricity generation mix. Heat is produced by both systems; LEDs generally reduce energy losses for the same lighting service, but performance depends on product quality and operating conditions.
• Could rebound effects occur (e.g., greater use because operation becomes cheaper or easier)?
  Possibly. Reduced operating cost may encourage longer lighting hours or less careful switching-off. If comfort improves, rooms may be used more often or for longer. Controls and policies can reduce rebound risk, but behavioural effects remain uncertain.
• Does the design depend on a future cleaner energy mix, or must it perform well under current conditions?
  The upgrade should perform under current conditions because efficiency reduces demand regardless of grid mix. A cleaner future grid strengthens benefits, but should not be the sole justification for early replacement if embodied impacts are high.

2.3 Waste, Circularity & End-of-Life

• What waste is created during manufacturing or use?
  Manufacturing waste is unknown at this stage (supplier dependent). During use, fluorescents generate recurring lamp waste (tubes) and packaging. LEDs can reduce lamp replacement waste but may introduce e-waste from drivers/modules when failures occur.
• Are any components being replaced early, before their useful life ends?
  Yes—potentially the existing fluorescent luminaires. This is a key circularity tension: early replacement creates waste and embodied impacts now. A phased approach (highest-need or highest-use rooms first) can reduce premature disposal.
• What happens to the system at end-of-life: reuse, remanufacturing, recycling, or disposal?
  Fluorescent tubes require hazardous waste handling due to mercury; fittings may be recycled as mixed materials. LEDs may allow recovery of some metals, but electronics and mixed materials can be challenging and may be downcycled or disposed depending on local infrastructure.
• Can materials be recovered at high quality, or only downcycled?
  Metals such as aluminium may be recovered at relatively high quality. Plastics and electronics are more likely to be downcycled or recovered at low rates. End-of-life quality depends strongly on product design and available recycling pathways.
• Are components easy to separate and repair?
  It depends on the chosen LED luminaires. Modular luminaires (replaceable drivers/light engines) improve repair. Sealed or integrated luminaires increase the likelihood of whole-unit replacement, undermining circularity.
• Can the system be upgraded without replacing the whole product?
  Potentially. If modular, drivers and light engines can be replaced without discarding housings. If not modular, upgrades may require full replacement. This should be treated as a procurement requirement rather than an assumption.
• Does the design encourage long service life (durability, modularity)?
  Unknown at this stage. Long life is only credible if spare parts, repair access, and supplier support are planned. Without this, “long lifetime” becomes an assumption rather than a design property.
• Could a “product-as-a-service” or leasing model improve reuse or recovery?
  Possibly. A service model could incentivise take-back, repair, refurbishment, and higher recovery rates. Feasibility is unknown at this stage and depends on procurement rules, suppliers, and contract structures.

2.4 Environmental Hotspots & Assumptions

• Which one to three life-cycle stages appear most harmful, and why?
  Likely hotspots are: (1) use-phase electricity (especially under the baseline); (2) manufacturing of LED luminaires (electronics and aluminium), particularly if replacing equipment early; and (3) end-of-life handling (mercury risk for fluorescents; e-waste risk for LEDs).
• Does the design reduce these impacts compared with the baseline?
  Likely reduces use-phase electricity and mercury-related waste over time. However, short-term impacts may increase due to embodied impacts of new luminaires and premature disposal of existing fittings. Whether the overall outcome is “better” depends on usage intensity, remaining life, and product repairability.
• What assumptions support your judgement (energy mix, materials, lifetime, user behaviour)?
  High operating hours in teaching rooms; meaningful efficiency gains; long LED lifetime; modular repairability; correct commissioning and use of any controls; realistic end-of-life recovery; and limited rebound behaviour.
• How uncertain are these assumptions, and how might conclusions change if they differ?
  Uncertainty is moderate to high. If usage hours are lower than assumed, if LEDs fail early or are not repairable, if controls are poorly implemented, or if recycling pathways are weak, the case for early replacement weakens and phased or targeted interventions become more attractive.
• Could scaling the solution (large deployment) create different or larger environmental risks?
  Yes. A campus-wide rollout increases demand for metals and electronics and concentrates end-of-life responsibility. The scale also increases potential benefits (energy savings) but amplifies procurement and waste-management risks.
• Would a more detailed LCA be needed to check or refine this early-stage reflection?
  Yes. An LCA comparing baseline vs LED options would test key assumptions (usage hours, remaining life, lifetime, repairability, energy mix) and quantify whether full replacement or phased replacement is environmentally preferable.

3 Social Reflection – Stakeholders & Values

This step examines how people are affected by the lighting system across its life cycle, focusing on stakeholders, values, equity, wellbeing, and potential unintended consequences.

3.1 Stakeholder Mapping

• Who are the direct users of the system?
  Students, teaching staff, visiting lecturers, and facilitators who occupy teaching rooms.
• Who is indirectly affected?
  Facilities management staff, maintenance teams, cleaning staff, room schedulers, and people using nearby spaces during installation.
• Are there groups easily overlooked?
  Individuals with visual sensitivities or conditions, temporary users unfamiliar with the rooms, and upstream workers involved in manufacturing and materials extraction.
• How does each group interact with the system?
  Users experience lighting directly; facilities staff operate and maintain the system; procurement teams make specification decisions; upstream workers are affected indirectly through supply chains.

3.2 Stakeholder Values

• What does each stakeholder group value?
  Users value visual comfort, clarity, and a welcoming learning environment. Facilities staff value reliability and ease of maintenance. Administrators value consistency and perceived quality of teaching spaces.
• Does the design support these values?
  Yes. Improved lighting quality supports comfort and consistency, aligning with the primary social motivation for the upgrade.
• Does the design risk undermining any values?
  Possibly. Poorly chosen brightness or colour temperature could reduce comfort for some users if not carefully specified and reviewed.
• Do some groups’ values dominate decision-making?
  User comfort and institutional image are prioritised. This appears justified given the socially motivated problem, but maintenance and upstream labour concerns should still be considered.

3.3 Equity, Inclusion & Accessibility

• Who gains the most and who gains the least?
  Frequent users of teaching rooms gain the most. People who rarely use these spaces gain little direct benefit.
• Could any group be excluded?
  Not applicable. Lighting is a shared service and does not restrict access based on cost or ability.
• Does the system consider users with different needs?
  Potentially. Improved uniformity and brightness can reduce disadvantage related to seating position or visual sensitivity.
• Is the system easy to use without specialised knowledge?
  Yes, provided controls (if installed) are intuitive and limited to necessary functions.
• Does the system increase workload or stress for any group?
  Temporarily for installation teams; potentially reduced workload for maintenance teams over time.

3.4 Safety, Work Conditions & Wellbeing

• What realistic safety risks exist?
  Installation work introduces short-term risks (working at height, electrical work). During use, lighting poses minimal safety risk.
• Does the system help people feel safe and in control?
  Yes. Improved lighting can enhance perceived safety and comfort in teaching spaces.
• Could system failure cause harm?
  Low risk. Failure would reduce lighting quality but is unlikely to cause direct harm.
• Do upstream processes involve hazardous or unfair working conditions?
  Possibly. Electronics manufacturing and materials extraction can involve labour and safety risks depending on sourcing practices.
• Could design or sourcing choices reduce these risks?
  Yes. Responsible procurement and supplier standards could reduce upstream social risks.

3.5 Unintended Social Consequences

• Could the system change behaviour in unintended ways?
  Possibly. Brighter or more pleasant rooms may encourage longer occupancy.
• Could digital features increase surveillance or reduce privacy?
  Not applicable, unless advanced monitoring or data collection features are introduced.
• Could burdens shift to certain groups?
  Yes. Poorly designed controls could increase user frustration or maintenance interventions.
• If widely adopted, who might be negatively affected?
  Upstream workers and communities could be affected if supply chains are not responsibly managed.

4 Economic Reflection – Cost, Viability & Supply Chains

This step examines who pays, who benefits, how costs evolve over time, and how resilient the system is to supply-chain, price, and geopolitical risks.

4.1 Cost Distribution

• Who pays for the system to be developed or installed?
  The university funds the upgrade through capital expenditure.
• Who pays to use or access the service?
  Not applicable. Lighting is provided as part of shared teaching infrastructure.
• Is cost a barrier for any group?
  Not directly. However, budget constraints may limit the speed or scope of implementation.
• Does the design shift costs between groups?
  Yes. Higher upfront costs are accepted by the institution in exchange for long-term operational savings.

4.2 Operating Costs & Lifetime

• What ongoing costs arise during use?
  Electricity consumption and periodic maintenance.
• Does the design reduce or increase these costs compared to the baseline?
  Likely reduces both energy and maintenance costs over time.
• How long is the system expected to last?
  LEDs typically have longer service lives than fluorescent lamps, though driver longevity is critical.
• Is repair easy and low-cost?
  Depends on luminaire design. Modular systems support repair; sealed units do not.
• Could early replacement create avoidable waste?
  Yes, if existing luminaires still have significant remaining life.

4.3 Supply-Chain & Resource Risks

• Does the system rely on scarce or difficult-to-substitute materials?
  Potentially. Electronics and rare earth elements may be involved.
• Are key materials sourced from a small number of countries?
  Yes. Some LED components are produced in globally concentrated supply chains.
• Could political or trade disruptions affect availability?
  Yes. Geopolitical tensions could affect component supply or pricing.
• Does the system depend on specialised skills or tools?
  Standard electrical skills are required; advanced dependencies are limited.
• What happens if prices rise?
  Higher material or energy prices would increase upfront costs but also increase the value of energy efficiency.
• Could design choices reduce supply-chain risk?
  Yes. Standardised, modular components and multiple suppliers improve resilience.

4.4 Long-Term Value & Resilience

• Does the system create long-term value?
  Yes. Lower operating costs, improved space quality, and alignment with energy goals.
• Does it support local skills or jobs?
  Limited direct impact, though installation and maintenance involve local labour.
• Is the design adaptable to future change?
  Yes, particularly if integrated with building management systems.
• Is the system economically robust or fragile?
  Moderately robust, with resilience depending on procurement choices and repairability.

5 Integrate, Compare & Reflect

This step brings together environmental, social, and economic insights to identify priorities, trade-offs, and next steps.

5.1 Cross-Dimension Summary

• What are the main environmental hotspots?
  Use-phase electricity (baseline) and embodied impacts of LED manufacturing.
• What are the key social issues?
  User comfort, inclusivity, installation disruption, and upstream labour conditions.
• What are the main economic risks?
  Upfront cost, supply-chain concentration, and repairability.
• Which dimension appears most challenging?
  Environmental trade-offs between early replacement and long-term energy savings.
• Do any issues span multiple dimensions?
  Repairability and modularity affect environmental, social, and economic outcomes.

5.2 Trade-Offs & Value Tensions

• Are there clear trade-offs?
  Yes. Improved comfort and energy efficiency versus embodied impacts of early replacement.
• Who benefits and who may be disadvantaged?
  Users benefit most; environmental costs occur earlier and upstream.
• Are any trade-offs unacceptable?
  Not at this stage, but early replacement in low-use rooms may be questionable.
• Could adjustments reduce trade-offs?
  Yes. Phased replacement and modular product selection can rebalance impacts.

5.3 Design Opportunities & Next Steps

• What concrete changes could improve sustainability?
  Specify repairable luminaires; prioritise high-use rooms; ensure effective control commissioning.
• Which questions remain unanswered?
  Actual usage hours, LED lifetime, recycling pathways, and supplier practices.
• What tools would support a next phase?
  Life-cycle assessment, procurement criteria, and post-installation user feedback.
• What direction does the reflection suggest?
  Proceed with the upgrade using a phased, circularity-informed approach.