Understanding carbon in renovation: what are we actually talking about?
Operational vs embodied carbon: the two things you need to know
In renovation, carbon plays out on two fronts. Operational carbon corresponds to emissions during the home's use: heating, hot water, ventilation, electricity. Embodied carbon comes from products and works: material manufacturing, transport, installation, maintenance, end of life.
Embodied energy: a simple definition and concrete examples on site
Embodied energy is the energy spent even before the site "heats up". A concrete example: producing an insulation product, an aluminium window or a bag of mortar, packaging them, transporting them, then removing and treating the waste. To make this objective, you rely on FDES and PEP data sheets via the INIES database.
Why the carbon footprint changes your technical choices (and your margins)
A carbon footprint helps you make decisions. Reuse, local materials, a well-adjusted heat pump output, this can reduce the impact while protecting your margin. Less oversizing, fewer call-backs, a clearer quote. In 2026, these arguments also matter in tenders where LCA becomes a criterion.
2026 carbon accounting method: how to calculate without getting overwhelmed
Scope to define from the quote stage: products, transport, installation, end of life
Start simple. Define a clear scope per work package. Include product manufacturing, journeys (supplier, site, skips), on-site machine energy, and end of life (removal, sorting, recycling or landfill). Without this framing, two quotes aren't talking about the same carbon.
Data to use: FDES, PEP, public databases and default values
Start with the EPDs to EN 15804 for the construction products and equipment you are using. Supplement with a public database such as the ICE inventory for embodied carbon, and the DESNZ factors for transport and energy. When a figure is missing, keep documented, stable default values rather than rough guesses.
Practical calculation: order of magnitude per work package (insulation, joinery, heating)
To move quickly, work in kgCO2e per unit. Example order of magnitude:
- Insulation: kgCO2e per m² installed, to compare material by material.
- Joinery: kgCO2e per window, separating frame and glazing.
- Heating: kgCO2e of the equipment, then energy during the use phase depending on the scenario (electricity, gas).
The right 2026 approach is to track your assumptions and keep the same method from one project to the next.
Embodied energy of common solutions: a useful comparison for your decisions
Reducing carbon without losing performance: concrete levers on site
Reuse and "no more than needed" renovation: when it's relevant and how to frame it
Reuse works when the product is accessible, checkable and compatible with the targeted performance. Before removal, carry out a proper assessment. Measure condition, airtightness, moisture risks, then define who checks what. On the framework side, plan simple traceability: photos, a handover sheet, storage conditions, and a written agreement on warranties and responsibilities.
Optimising quantities and offcuts: layout planning, formats, logistics and storage
You reduce carbon without touching the R-value. You act on the excess metres. Work out a cutting plan as early as the take-off stage. Choose suitable formats, group thicknesses together, and secure storage to avoid rework. Layout planning starts from accurate take-offs, and the areas recorded during the visit feed the quantities in the quote directly.
- Layout planning, ordering as close as possible to actual need, controlled returns.
- Sorting offcuts, internal reuse, local supply chains.
Choosing suppliers and transport: short circuits, consolidated loads, traceability
Favour manufacturers with FDES or PEP data available, and reliable delivery. Plan the rotations. One consolidated run is often better than three small drop-offs. Keep simple evidence: delivery notes, product references, and origin. You protect quality, and you cut unnecessary kilometres.
Proving your carbon approach to clients and for grants: evidence, documents, limits
What you can document simply: product data sheets, FDES/PEP, photos, delivery notes
To track your carbon, keep product data sheets and exact references (brand, model, performance). Add, where they exist, the FDES for materials and the PEP for equipment. Take dated evidence before, during and after. Photograph labels, serial numbers, installed thicknesses. Also keep delivery notes and, if you remove waste, disposal receipts.
2026 funding and requirements: points to watch
On the funding side, your required documents must match current rules. Quotes and invoices must state the company, its registration for the measure, performance figures and dates. On a funded whole-house retrofit, PAS 2035 requires an assessment and a retrofit coordinator overseeing the project. Archive the measure specification, the signed declarations, and proof of performance. During an audit, the surface area, output and references must match.
Avoiding mistakes: "low-carbon" claims, misleading comparisons, missing data
To avoid disputes, avoid green claims without a method behind them. Never compare two solutions if the scope changes (use, lifespan, quantity). If an FDES is missing, say so and stick to verifiable elements. It's better to state "partial data" than to promise an unprovable carbon gain.
