ESOS Phase 4 Is Coming. Is Your Organisation Ready?

The Energy Savings Opportunity Scheme (ESOS) is one of the UK's most significant mandatory energy auditing frameworks — yet for many large organisations, each compliance cycle brings the same challenges: rising consultancy costs, internal resource pressure, and audits that feel like a box-ticking exercise rather than a genuine driver of energy efficiency.

At Zerith, we believe ESOS should be different. That's why we've developed two distinct pathways that give UK organisations the flexibility to comply smarter — whether you want a fully managed service or the tools and expertise to lead your own submission.

The Problem with Traditional ESOS Compliance

Traditional ESOS compliance typically means handing the entire process to an external consultancy. For many organisations, this works — but it comes at a cost. Fees can be substantial, timelines are driven by the consultant's schedule, and your internal teams often end up disengaged from findings that could genuinely transform your energy performance.

There's also a missed opportunity: your Building Managers, Energy Managers, ESG leads, and Engineering teams hold invaluable knowledge about your estate. Too often, that expertise goes untapped.

Two Smarter Paths to ESOS Compliance

Option 1 — Zerith Managed ESOS: Consultancy Reimagined

For organisations that want a fully managed ESOS submission, our Managed ESOS service delivers everything you'd expect from a leading energy consultancy — but with one important difference: efficiency built in from day one.

Using the ZECO AI Platform, our consultants accelerate every stage of the ESOS process, from data gathering and site assessments through to report generation and compliance sign-off. The result? The same rigorous, fully compliant ESOS submission — at a typical saving of 10–15% compared to traditional consultancy pricing.

"ESOS compliance without compromise — delivered faster, at lower cost, and backed by Zerith's team of qualified Lead Assessors."

This pathway is ideal for organisations that want complete peace of mind, minimal internal resource commitment, and the confidence that comes from working with experienced ESOS specialists.

Option 2 — Zerith Supported Self-Delivery: Take Control of Your ESOS

For organisations with established in-house expertise, our Self-Delivery pathway is a genuine game-changer. This model enables your own Building Managers, Energy Managers, ESG professionals, or Engineering teams to lead and deliver your ESOS submission — fully supported by Zerith consultants and the ZECO AI Platform, with a Zerith Lead Assessor providing sign-off.

The savings are significant:

• 30 to 50% savings. Single-site organisations can typically save around 30% to 50% compared to traditional approaches.

• 50–70% savings. Multi-site organisations can unlock savings of 50–70% compared to traditional consultancy fees

This approach is particularly well-suited to:

• Any client who has a strong internal capability (for example, major CRE buildings, CRE portfolio operators, industrial and manufacturing sites, hotels and leisure operators) — where you have facilities, engineering, energy or ESG teams who have strong existing knowledge of the estate.

• Professional services firms and tenants in commercial office buildings, where energy opportunities can be limited and the ability to rapidly identify and evidence relevant assets is critical to keeping compliance costs proportionate.

• Any organisation that wants to take genuine ownership of its ESOS process, build internal capability, and ensure findings translate into real action.

"The ZECO AI Platform puts the power of professional-grade ESOS delivery in your team's hands — with Zerith expert support at every step."

Not Sure if Your Organisation Needs to Complete ESOS?

ESOS applies to large UK organisations that meet specific thresholds based on employee numbers, turnover, and balance sheet size — but eligibility isn't always immediately obvious, particularly for subsidiaries, joint ventures, or organisations that have grown or restructured in recent years.

To make it easy, we've built a free ESOS Eligibility Checker on the Zerith website. In just a few clicks, you can find out whether your organisation is required to comply with ESOS Phase 4 — and if so, what your next steps should be.

"Not sure if ESOS applies to you? Use our free Eligibility Checker at zerith.uk/energy-compliance-consultant — and get clarity in minutes."

If you're confirmed as in-scope, our team is ready to help you choose the right compliance pathway and get started straight away.

Why Zerith?

Zerith was founded on a simple belief: that energy compliance should create value, not just cost. Our ZECO AI Platform has been purpose-built to make ESOS delivery faster, more accurate, and more accessible — whether your team is completing the assessment themselves or working alongside ours.

Every Zerith ESOS submission is signed off by a qualified Lead Assessor. Every finding is actionable. And every client — regardless of the pathway they choose — benefits from the same rigorous, expert-backed approach that has made Zerith a trusted partner for UK energy and ESG professionals.

Get in Touch

Whether you're exploring your ESOS options for the first time or looking to make your next compliance cycle more efficient, we'd love to talk. Contact the Zerith team today to find out which pathway is right for your organisation.