Contact Us
Member Login

Your cart is empty




Training now released for the Energy Savings Opportunity Scheme!


The Energy Saving Opportunity Scheme (ESOS) comes but once every four years, and yes, it’s that time again!

What is ESOS?

ESOS is a mandatory energy assessment scheme for eligible organisations in the UK. It applies to large undertakings, which includes businesses, not-for-profit bodies and other non-public sector undertakings. Eligible organisations must instruct a qualified ESOS Lead Assessor to complete an ESOS Audit, which they will then submit to the Environment Agency.

But here’s the exciting part for Energy Assessors: only those with two years’ relevant experience can train to become ESOS Lead Assessors! This role is therefore a natural fit for Non-Domestic Energy Assessors (NDEAs) and Display Energy and Certificate (DEC) Assessors and Energy Auditors

Why become an ESOS Lead Assessor?

ESOS is more detailed than a commercial energy assessment and would therefore suit those looking to progress in their careers and move into an energy consultancy role.

You have more freedom to delve into areas in more depth and to work closely with clients to provide energy advice. It’s also a useful tool for helping organisations achieve net zero, and helping support the UK government’s goal of achieving net zero carbon emissions by 2050.

Due to the specialised nature of this work most ESOS Lead Assessors choose to charge a day or hourly rate – making it a potentially lucrative area of work.

Elmhurst’s Head of Operations and former Non-Domestic Team Leader Josh Wakeling commented: “ESOS is a fantastic scheme and brilliant opportunity for energy assessors as it builds on their knowledge and experience gained as either non-domestic or DEC energy assessors.

“Not only does ESOS look into improving the energy efficiency of buildings in more depth than the SBEM or DEC assessment methodologies, but it also delves into transport and industrial process energy use. It is very much more of an energy consultant and energy manager role. I highly recommend ESOS for those looking at net zero and wanting to assist large organisations in reducing the energy consumption and carbon emissions, and ultimately saving them a lot of money.”


In July 2021 the Department for Business Energy and Industrial Strategy (BEIS) released a consultation outlining some exciting proposed changes to the ESOS scheme. This included, extending the scheme to medium-sized enterprises (MEs) and making ESOS data publicly available.

What is the process of completing an ESOS Audit?

The ESOS Lead Assessor visits the site and collects detailed energy data relating to the building, transport and industrial processes. You may have to visit more than one site if a company has more than one premises.

Once they have visited all sites and got the data, they look at how to reduce the organisation’s energy use and prepare a big report which they present to the board of the company to sign off. This report is then submitted to the Environment Agency, which is the scheme administrator.

The compliance periods

Although the compliance period for ESOS Phase 3 seems like a long way away (5th December 2023), most ESOS Lead Assessors will start gathering data around the summer period, in order to collect 12 months of energy data and have enough time to process it. 

Phase Qualification Date 4 Year Compliance Phase Compliance Date
Phase 1 31st December 2014 6th December 2011 – 5th December 2015 5th December 2015
Phase 2 31st December 2018 6th December 2015 – 5th December 2019 5th December 2019
Phase 3 31st December 2022               6th December 2019 – 5th December 2023                5th December 2023
Phase 4 31st December 2026 6th December 2023 – 5th December 2027 5 December 2027

How do I become an ESOS Lead Assessor?

You can become an ESOS Lead Assessor by joining Elmhurst’s four day course. The course covers everything you need to know to confidently carry out energy audits, including a practical day which is unique to the Elmhurst course! After completing the course and successfully passing the exam, you can join Elmhurst’s approved scheme and start completing ESOS assessments.

Already qualified?

If you’re an ESOS Lead Assessor with another scheme, all you have to do is complete our AP95 form and select ‘Route 3’ in section 4 of the application form. Upon successfully completing the exam you can join Elmhurst’s scheme.

Find out more about ESOS Training