Methodology

How the estimate works

The screen estimates your Energy Savings Opportunity Scheme (ESOS) Phase 4 programme from your answers. It uses Hyphora’s Stage 2 sampling method and fee table, simplified for a screen. No AI is used in the calculation. The same answers always give the same result, and an ESOS Lead Assessor checks every screen before it is sent.

1. Whether you qualify

You are in ESOS Phase 4 if any UK company in your group is a large undertaking on 31 December 2026: 250 or more staff, or turnover over £44m and a balance sheet over £38m. Public sector bodies are not in ESOS. We call it borderline if your staff number is between 238 and 262, if one financial test passes and the other is within 10%, or if you aren’t sure about your group. Borderline screens still get a full estimate.

2. Your total energy use

We add your buildings’ electricity, gas and other fuels to your transport energy. If you gave spend rather than kWh, we divide it by the government’s average business price for that fuel, and the screen says so. Fuel in litres is converted at its gross calorific value. Mileage is converted to carbon and then to kWh with the government conversion factors.

3. Which buildings are audited

We don’t audit every building. ESOS lets you audit a representative sample and apply the findings to similar sites, so we group your sites by how they use energy and choose which to audit in each group. Your Lead Assessor sets the sample in your sampling plan.

• A Tier 2 site audit is a remote review of the site’s meter data plus a site visit. ESOS requires a site visit, so every plan has at least one.
• A Tier 1 desktop audit is a remote review with no visit. It covers buildings that differ from the ones we visit, for less than the cost of a visit.
• A site without a smart or half-hourly meter can’t be reviewed remotely, so any audit there is a site visit, and the screen says so.

The screen gives a headline estimate, and an upper end in case your buildings vary more than your answers suggest.

4. The price

The price has three parts: a Lead Assessor fee, set by how many legal entities and sites you have, which covers the planning, data, sampling plan, transport analysis, report, action plan, filing and sign-off; a fixed price for each building audited, by tier; and transport. A single office for a single entity, with no company vehicles, has one all-in fee. Where you have process energy use, we price the audits with you on a call.

Transport depends on the vehicles you use. With no fleet, or only staff’s own cars and hire cars, we review it from your records as part of the Lead Assessor’s work. If you own or lease cars, vans or minibuses up to 3.5 tonnes, there is one fixed-price transport audit, however many vehicles you run. Heavy goods vehicles, plant, refrigerated vehicles, or transport as your core business, need a written quote.

Your price is in the screen we send you, after our ESOS Lead Assessor has checked it. It is confirmed by your sampling plan, and moves only by the published price of each building added or removed. Prices exclude VAT, and travel is charged at cost.

5. When to start

We count back from the 5 December 2027 deadline for notifying the Environment Agency: 4 weeks for reporting, the audit weeks (at least 3, at 2 visits a week), 8 weeks for planning and an 8-week buffer, because Lead Assessors are busiest near the deadline. Less than 8 weeks to that start date is red, less than 16 amber.

6. Data readiness

• Green: your data is on an energy platform or with a bureau, most sites are half-hourly metered, and transport is known.
• Amber: bills site by site, transport only partly known, or some sites supplied through a landlord.
• Red: you aren’t sure where your data is, you run vehicles with no fuel figures, or more than 20% of sites are landlord-supplied.

What the screen can’t tell you

It is an estimate from your answers, not a quote or legal advice on whether you qualify. Group structures, landlord-supplied energy and your figures on 31 December 2026 can change the result. We confirm the scope and give a fixed quote after a 30-minute call.

Sources and dates

• Dates and thresholds: GOV.UK, How to comply with ESOS Phase 4 (checked 4 November 2026).
• Prices: Hyphora ESOS price list, as at 5 November 2026.
• Sampling: Hyphora sampling rules, as at 5 November 2026.

Questions about the method? Book a 30-minute call.