GN4.6: Undertaking an energy audit

Guidance Note purpose 

The purpose of this Guidance Note is to provide information for asset managers, property managers and facilities managers about the arrangements involved in undertaking an energy audit. 


Energy audits are a form of assessment which help to establish the way in which energy is used in a property, to determine whether energy management arrangements are being followed and are effective, and to identify opportunities to improve energy management and performance. 

An energy audit can be undertaken as a stand-alone exercise, or as a component of an energy management system. Alongside electricity, oil and gas used within a property, energy audits may include energy consumed by transport associated with a building, temporary on-site equipment and emergency generators. 


Legislation and certifications  

The UK Government’s Energy Saving Opportunities Scheme (ESOS) requires that organisations that meet criteria relating to the size of their UK operations must undertake an energy audit every four years.  The deadline for the second compliance for ESOS was December 2019. 

ESOS is the UK’s transposition of article 8 of the EU Energy Efficiency Directive.  This regulation sets specific requirements for qualifying companies to identify and review high areas of energy consumption, with an expectation that this will raise awareness, and encourage adoption, of energy saving measures. 

Business opportunities 

Certification schemes, for example ISO50001, demonstrate the implementation of effective Energy Management Systems at the company, portfolio or property level.  A requirement of such schemes is to provide evidence that a regular energy audit is undertaken, and that the outcomes are acted upon. 

As well as contributing towards the development of energy saving initiatives and the enhancement of energy management arrangements, energy audits can inform refurbishment plans and the effectiveness of maintenance regimes.  The results of energy audits can also be used to engage employees, occupiers and suppliers and drive energy efficiency behaviours. 

Responsibilities & Interests

The table below summarises the key activities associated with energy audits, and highlights where asset managers, property managers and facilities managers are likely to have a responsibility or specific interest. 

AM - Asset Manager
PM - Property Manager
FM - Facilities Manager

Step 1.Establish audit oversight and scope 


Step 2. Secure a competent energy assessor  


Step 3. Review energy consumption 


Step 4. Review energy management arrangements 


Step 5. Identify improvement opportunities 


Step 6. Review and continue to improve 


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How to



An energy audit is usually established at the property level, although it is possible to combine an audit across multiple sites, and a program of energy audits is often undertaken at a portfolio level.  

The decision to implement an energy audit, either as part of an Energy Management system or independently, is usually taken by an asset manager.  A property manager will most often be responsible for coordinating the audit process, with information and support provided by a facilities manager.  The audit outcomes will be of interest to all stakeholders. 

The process of undertaking an energy audit should take place within a wider framework for the governance of audit and assurance activities, and should include the following steps: 

Step 1: Establish audit oversight and scope


It is important that a forum, committee or body is established to provide oversight of the audit process, to validate outcomes, and to check that recommended actions are allocated appropriately.  

Determining the audit scope should involve consideration of a number of issues, including: 

  • Is it beneficial to include occupier leased areas as well as owner-controlled areas? 
  • Should services and equipment managed by occupiers be included? 
  • What fuel types will be included, for example, transport fuel, renewable energy systems, CHP installations? 

Step 2: Securing a competent energy auditor


An energy audit should be undertaken by a competent energy assessor.  As the qualification and accreditation required by certain regulations, rating and certification schemes and property types vary, it is important to check if there are specific requirements for the planned audit. 

As a minimum, an energy auditor should have experience in relation to: 

  • Energy management. 
  • The property and equipment type involved. 
  • The processes and arrangements involved in audit and assurance activities. 

Step 3: Review energy consumption profile


The preparation of a property’s energy consumption profile is a central element of an energy audit.  This should include, as a minimum, total energy consumption, broken down by energy type, source, user.  Options to include additional variables, for example, seasonal fluctuations and weather days, should also be considered. 

The energy consumption profile should be compared against historical trends, with the intention of identifying the areas of greatest consumption and anomalies in expected consumption. 

Step 4: Review energy management arrangements


Performance against historical energy targets should be reviewed to determine the extent that progress towards intended improvements is on track.  

Alongside this, an energy audit should consider management arrangements, such as processes to monitor and review energy consumption, or to check that recommended actions from previous energy audits are being deployed.  There should be evidence that such arrangements are in place and are being implemented. 

Step 5: Identify energy opportunities


A key component of an energy audit is to identify opportunities to improve energy efficiency.  This is partly informed through the analysis of a property’s energy consumption profile and is complemented by general observation of equipment and operational practices. 

This could include, for example, where plant, equipment and services are in operation outside working hours or where routine maintenance is behind schedule.  Specialist knowledge and experience may be required when considering whether building fabric, plant and equipment is in need of renewal. 

Alongside energy saving interventions, an energy audit may also consider opportunities to improvement wider energy management activities.  For example, the metering arrangements for recording and collating energy data, or how energy efficiency awareness raising is undertaken. 

Step 6: Review and continue to improve


The outcomes from an energy audit, including recommended improvement actions, should be documented and reviewed by the oversight body.  An action plan should set out improvement opportunities alongside timeframes and responsibilities and should inform the development of energy targets. 

Ongoing energy consumption, progress against targets and the implementation of action plans should be periodically reviewed by the oversight body, or an appropriate forum with responsibility for a property’s energy or environmental management activities. 

Related Guidance Notes 

The following Guidance Notes contain related information: 

Additional Resources