An energy performance guarantee is not a commercial turn of phrase, it is a contract whose minimum content is written down. The French order of 24 July 2020 defines the energy performance contract as a contract between a client and an energy efficiency services company aimed at guaranteeing a fall in consumption, backed by financial penalties if the target is missed. It requires a baseline covering at least three consecutive calendar years before signature, expressed in kWh per year and adjusted for the external factors that influence consumption, then a savings target expressed as a percentage of that baseline, between 1% and 100%. That mechanism, not goodwill, decides who pays when the result is not there.
Understanding the energy performance guarantee and the performance contract
The difference between a best-efforts obligation and a performance guarantee (results obligation)
On a standard job, the tradesperson is usually under a best-efforts obligation: they implement techniques that comply with accepted standards, without promising a specific consumption figure. With a performance guarantee, you contract around a measurable target (kWh, euros, temperature, comfort). If the target isn't met under the agreed method, corrective actions or compensation may apply.
The work involved: insulation, heating, ventilation, regulation
Performance is rarely determined by a single trade. Contracts generally cover a "package" of work, to limit air leaks and setting drift.
- Insulation and treatment of thermal bridges.
- Heating, hot water production, and balancing.
- Ventilation (flow rates, maintenance, air quality).
- Regulation and control, with usage monitoring.
Who commits to what: tradesperson, engineering firm, operator, client
The engineering firm sets the baseline and does the sizing. The tradesperson commits to correct execution and settings. An operator may hold the performance contract and organize measurement over time. The client provides the data, follows the usage instructions, and handles maintenance. In 2026, clarity of responsibilities makes all the difference.
What the contract has to contain
Four elements structure the contract, and each is written before signature. A contract missing one of them is not an energy performance contract, it is a promise.
| Element of the contract | What the text requires |
|---|---|
| Baseline | at least three consecutive calendar years before signature, adjusted for the external factors that influence consumption, expressed in kWh per year |
| Energy savings target | expressed as a percentage of the baseline, between 1% and 100% |
| Financial penalty | a function of the consumption gap measured against the contractual commitment |
| Verification | may be carried out by a third-party body accredited to ISO/IEC 17020 |
The baseline decides everything else, and it is also the part most often rushed. Three years of bills is what absorbs one mild season and one hard winter. Adjusting for external factors is what stops you paying for a change of occupant, an extension of the heated floor area or a setpoint raised by two degrees.
The line with an obligation of means, and why you cross it in writing
Without a contract of this kind you stay under an obligation of means: you have to apply techniques that meet good practice, not to hit a number. The moment you write a figure with a financial consequence attached, you move to an obligation of result, and both your insurer and your client will read it that way. The question to settle before signing is therefore not whether you can hold the performance, but whether you control the factors that determine it. Settings and workmanship are yours, use and weather are not, and that is precisely why adjusting the baseline is not a comfort clause. That written commitment has to come back signed and dated, which is what electronic signature built into the journey, on site or remotely, with the signed document returning to the file is for.
Framing the targeted performance: indicators, method, and evidence to produce
Choosing clear indicators: kWh/m²/year, actual consumption, summer/winter comfort
Set 2 or 3 benchmarks. A target in kWh/m²/year (derived from an energy performance certificate or an audit). Monitoring of actual consumption via bills or remote metering, distinguishing heating, hot water, and possibly cooling. And a comfort indicator, for winter (temperature reached) and summer (overheating, perceived comfort).
Defining the scope: usage, weather, occupancy, equipment, and settings
Performance depends on the framework. Specify the usage included, the reference weather, including the degree-day base and the station used, occupancy, internal gains, and equipment. Note the key settings (setpoints, heating curve, ventilation, schedules). Otherwise, an "energy saving" could come from a change in behaviour rather than from the work itself.
Measurement and verification: readings, metering, monitoring, and handover reports
Before, during, after. Keep simple evidence. Meter readings, photos of labels and settings, commissioning records, and 12-month monthly monitoring. The handover report lists tests, reservations, and documents delivered. That's your baseline for the guarantee.
- Metering plan and measurement points.
- Up-to-date manuals, as-built files, diagrams, and certificates.
- Test results where they exist (flow rates, balancing, airtightness).
Drafting a solid performance contract: clauses that protect your guarantee
Essential clauses: targets, tolerances, duration, responsibilities, and exclusions
Set measurable targets (kWh, euros, comfort). Define the measurement method, the tolerances, and the commitment period. Clarify who does what between the works, operation, maintenance, and consumption monitoring. Add exclusions that prevent disputes (how the home is used, extensions, change of occupants, deliberate overheating). That's the basis of a guarantee that's easy to read.
Fine-tuning and setup plan: hydraulic balance, ventilation, programming
Include a dated fine-tuning plan. It should cover the hydraulic balance of the networks, ventilation flow rates, the heating curve, setpoints, and programming. Plan for a settings report and the handover of the manuals, so performance doesn't stay on paper.
Managing gaps: corrective actions, penalties, guarantee cap, and timeline
Organize the handling of gaps with a timeline. Diagnosis within X days, corrective actions, then a check. Plan a simple penalty or bonus mechanism, a guarantee cap, and the conditions for accessing data. You stay in control, without promising the impossible.
Limiting field risk: best practices for holding the guarantee day to day
Before the works: energy audit, technical visit, points of vigilance, and detailed quote
Before starting, secure the project with an energy audit or, at minimum, an on-site technical visit. Note the constraints. Existing ventilation, humidity, networks, access, drainage. Record them in the quote with clear assumptions and reservations if needed. A well-framed quote avoids misunderstandings that weaken the guarantee.
During the job: installation quality, traceability, product data sheets, photos, and checks
Install according to the applicable British Standards and manufacturer manuals. Keep simple traceability. References, serial numbers, technical data sheets, energy labels. Take photos at key stages before closing up. Run checks. Airtightness, settings, functional tests. This on-site evidence protects the guarantee in case of a dispute. It is built up as the job goes, with photos, progress and snagging gathered in the job file.
After the works: client support, manuals, maintenance, and consumption monitoring
At handover, provide a clear file. Plans, manuals, product data sheets, test reports, usage instructions. Explain the maintenance. Filtering, cleaning, contract, and frequency depending on the equipment. Offer a check-in after 1 or 2 months to verify the settings and monitor consumption. This follow-up limits callbacks and secures the guarantee.
Financing and compliance in 2026: aligning guarantee, performance, and contract
Certification, insurance, and responsibilities: guarantees, professional indemnity, subcontracting, and joint contracting
In 2026, the funding and the insurance-backed guarantee are decided as early as the quote stage. Check that your registration is up to date for the relevant measure. Also make sure professional indemnity and public liability cover are active. In subcontracting, formalise the assignments and require proof of insurance. In joint contracting, clarify who handles the handover and the performance commitments.
Link with the funding: documents to provide and consistency of performance targets
The schemes require detailed quotes and invoices, with your certification, product specifications, and treated surface areas. Align the announced performance, for example the U-value an insulation reaches or the efficiency of a heat pump, with the assessment or the funded retrofit plan. That's the best way to avoid a payment being blocked or a request for further documents.
Documents to hand over: handover report, as-built file, certificates, and evidence
Hand over a dated handover report. Add a simple as-built file, manuals, diagrams, technical data sheets, and photo evidence. Plan for the completion certificate and the client declaration, signed and consistent with the invoices.
