Benefits of registration

Organisations who are required to comply with ESOS can appoint a Lead Assessor who is a member of an approved professional body register to conduct an ESOS assessment as a way of complying. The IEMA ESOS Lead Assessors register enables individuals to demonstrate professional competence in energy assessments to their organisation, clients and colleagues. For wider information on ESOS you can visit the government’s ESOS webpage here: Energy Savings Opportunity Scheme (ESOS) - GOV.UK (


To be eligible to apply for IEMA’s ESOS Lead Assessor Register members need to be at least ONE of the following:

  • A Principal Environmental Auditor;
  • A Full Member of IEMA and an Environmental Auditor (EA).

Along with the above, members will also need to demonstrate the following:

  • A minimum length of two years professional energy assessment and energy audit experience relevant to PAS 51215:2014, e.g. in energy management, energy auditing, energy management systems;
  • Involvement with two or more energy efficiency assessments/audits (either as an assessment team member or as the lead assessor);
  • Show evidence of leading audits/assessments for large organisations.

Application Process

Applications to the ESOS Lead Assessor register are assessed by an External Panel using the competencies in PAS 51215:2014 and evidenced through relevant training and experience and membership of professional bodies, external verification checks (see below) and successful completion of a one-day training workshop. The timeframe for approval under our external panel assessment process can vary, however, it will usually take around 3 weeks. Please note that candidates can only re-apply for ESOS Lead Assessor status twice within any 12-month period

External Verification Checks

For each application received, IEMA contacts the verification sources provided (minimum of three) to check that the work as described was undertaken, for the stated length of time and was of an acceptable standard. IEMA is not interested in the findings of audits or any confidential information.

Training Workshop

This one day workshop is a mandatory part of the application process to join IEMA’s Lead Assessor register. It is also available to attend as a stand-alone workshop if you can demonstrate that you have the correct level of knowledge and experience and that you are actively working towards meeting IEMA’s membership eligibility criteria to become an ESOS Lead Assessor:

  • The training day will only count towards an application to join IEMA’s Lead Assessor register in conjunction with a successful application and assessment.
  • All attendees are expected to have a background in energy management methods and demonstrate they have the experience set out under Eligibility. The course is not appropriate to new entrants.
  • Attendees will be required to complete pre-course reading, prepare a case study and complete a self assessment against the technical and non technical knowledge and skills required of an ESOS assessment team before attending the course.

Please note that these workshops are run subject to demand. For more information about workshop dates and prices please click here.