We make energy audits simple, actionable and cost-effective.
ista's audits go beyond the ESOS requirement. We reveal hidden inefficiencies, optimise energy use and strengthen your long-term strategy.
Unlock the full potential of energy compliance.
Rely on comprehensive ESOS and SECR compliance
Identify energy-saving opportunities and reduce costs
Minimise the risk of penalties for non-compliance
Benefit from ista's expertise and 100% success rate in energy audits
Your one-stop solution for energy audits.
In the face of rising costs and strict UK regulations, it is crucial to understand how your business uses energy. In the UK, large companies are required to carry out an Energy Saving Opportunities Scheme (ESOS) audit every four years. Therefore, ESOS is a measure to reduce unnecessary energy consumption, combat climate change and improve energy security.
However, compliance should not just be a tick-box exercise to avoid penalties: it is about using less energy, releasing less carbon and keeping more money within your business. ista is a leading expert in energy compliance. Our energy audits are designed to uncover hidden inefficiencies, highlight opportunities for savings and provide practical recommendations that deliver a measurable return on investment (ROI).
Fully compliant audits are tailored to the specific needs of commercial and industrial facilities. By combining on-site expertise with advanced digital analysis, we simplify the audit process while helping your organisation discover energy-saving avenues and strengthen its sustainability strategy.
Save costs, stay compliant, and build a more efficient business – with ista.
What is ESOS?
Introduced in 2014 under the EU Energy Efficiency Directive, the Energy Savings Opportunity Scheme is now a UK-wide compliance scheme administered by the respective Environment Agency. Its purpose is to help large organisations cut energy use, improve efficiency, and contribute to the UK’s net zero targets.
Qualifying businesses must complete a comprehensive audit covering buildings, industrial processes and transport every four years. This assessment identifies cost-effective ways to save energy, reduce emissions and improve long-term performance.
In short, lowering energy consumption also means lowering carbon emissions. For businesses, this translates into reduced costs, stronger sustainability credentials, greater appeal to investors, and increased resilience.
Who must comply with ESOS?
ESOS applies to all large UK organisations that meet either the employee threshold or both financial thresholds:
• 250 or more employees
OR
• Annual turnover above £44 million
• Annual balance sheet total above £38 million.
If your organisation or business is a 'large undertaking' or part of a group where an entity is a 'large undertaking', you must comply with ESOS. Although this primarily affects large businesses, it can also apply to non-profit organisations and other non-public sector undertakings that meet the relevant criteria. If your organisation qualifies, you must complete your annual and end of phase compliance requirements or face regulatory fines and being publically listed as non-compliant.
What does an ESOS energy audit include?
The audit examines your total energy usage across buildings, industrial processes, and transport. It analyses consumption patterns, benchmarks performance, and identifies opportunities to reduce waste.
The process typically involves five key steps:
- Calculate total energy consumption, covering all business activities.
- Identify significant areas of consumption accounting for at least 90% of your overall energy use.
- Appoint a lead assessor, who is a qualified expert that will guide and validate the audit. As well as complete site specific audits that represent your estate.
- Submit a compliance notification to the respective Environment Agency, confirming completion.
- Maintain clear records to demonstrate how your audit was carried out.
Each assessment concludes with a detailed report and prioritised recommendations. Although compliance is mandatory, ista ensures that the audit delivers real value by uncovering savings, strengthening your business's sustainability performance, and preparing it for long-term net zero goals. With many years of experience, ista UK can manage every step of the process in a smooth and efficient way. As fully qualified lead assessors, we will take care of compliance from start to finish.
The ista approach: Turning audit obligations into opportunities.
Energy audits are now an essential part of running a sustainable and competitive business. They help to identify energy-saving opportunities, reduce significant areas of consumption and demonstrate a commitment to sustainability to stakeholders. However, identifying inefficiencies across multiple sites and converting audit data into tangible improvements can be challenging, especially when industrial processes are involved.
ista makes energy audits straightforward. We carry out ESOS-compliant audits, adapting them to suit the specific needs of commercial properties and complex industrial operations. Our experts review electricity, gas, heating and building systems in detail and provide a clear report with prioritised recommendations and projected ROI. This means that you will not only meet your regulatory obligations, but also gain actionable insights that will help you to reduce costs and improve efficiency.
ista goes beyond compliance by providing expert support to help you implement energy-saving measures and link the results directly to your wider efficiency and sustainability goals. With optional integration into our Energy Management services, including real-time monitoring and digital tools, we ensure that the value of your audit extends well beyond the final report.
Turn your audit obligations into opportunities – with ista.
Choose the energy audit that fits your business.
There a several routes to ESOS compliance and the scope of an energy audit can vary depending on the needs of your organisation. At ista, we provide audits tailored to the commercial and industrial sectors in the UK. By offering these different levels, ista ensures that your business receives the appropriate level of insight and support, whether you are seeking quick wins, ESOS compliance, or a long-term net zero strategy. These include:
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Walk-through (Preliminary): Audit A quick, high-level inspection that highlights obvious inefficiencies and “low-hanging fruit” savings. Ideal for smaller sites or as an entry point into the audit process.
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Detailed Energy Audit: A full review with in-depth data analysis, system checks, and tailored recommendations. This level of audit is most often used to meet ESOS compliance requirements in the UK.
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Investment-Grade: Audit An extensive evaluation that supports major energy efficiency projects. It includes detailed financial modelling and ROI projections, helping senior decision-makers justify large-scale investments with confidence.
Benefits of SECR at a glance.
Enhance transparency.
An audit provides a clear picture of how your organisation consumes energy across buildings, transport and industrial processes, making it easier to understand where improvements can be made.
Cut cost.
By identifying inefficiencies and waste, energy audits reveal practical measures that lower operating expenses and unlock measurable savings.
Stay compliant.
In case your organisation must carry out ESOS audits, regular assessments ensure you meet all legal obligations, avoid penalties and demonstrate responsibility to regulators, investors and stakeholders.
Our smart and future-proof devices for a smoother experience.
Combining our one-stop solutions with innovative technology in our devices means that managing your metering options has never been easier. Find out more about the devices that complement the ista eco-system for your property.
MinuteView
istaCare
Energy audits with ista: Compliance and beyond.
Energy audits are a powerful tool for improving energy efficiency and moving your business towards a more sustainable and cost-effective future. They help you meet ESOS requirements and provide actionable insights to reduce costs and improve performance. While some companies treat audits as a one-off compliance step, ista ensures they become a long-term driver of efficiency.
Real-time energy data with MinuteView.
Accurate audits rely on reliable data. MinuteView gives you instant visibility into electricity, gas, heating and water consumption across multiple sites, all within a single platform. By linking this real-time data directly into your energy audits, ista ensures assessments are based on clear, up-to-date evidence — making compliance easier while highlighting opportunities to cut costs and improve efficiency.
Turn audit insights into action: plan your energy efficiency roadmap.
Your energy audit. Done in 6 easy steps.
ista makes energy audits straightforward with a clear, step-by-step approach. From the first consultation to follow-up support, we guide you through every stage of the audit:
Collecting:
We start with collecting meter data, energy bills and site information to understand your operations.
On-site inspection:
In an on-site inspection our experts assess building systems, controls and day-to-day practices across your facilities.
Analyse:
We analyse energy usage patterns, benchmark them against industry standards, and pinpoint inefficiencies.
Deliver:
We deliver a compliant audit report, ready for ESOS.
Continuous optimisation:
AI-driven analytics and automated reporting help to improve long-term efficiency and ensure compliance.
Follow-up support:
As part of our follow-up support, you can track progress and continue optimising long after the audit is complete with optional integration into ista’s monitoring platforms.
What sets us apart? Expertise you can trust!
With years of experience and a deep understanding of energy billing requirements, we set the industry standard for precision, reliability, and innovation.
3.7 mil. t of CO₂ emissions avoided
60 mil. devices
43 mil. transmitting devices
68 years of metering experience
14 mil. apartments/commercial units
The next ESOS deadline – and the risks of ignoring it.
ESOS operates in four-year phases, and UK businesses are currently in Phase 4, which has a compliance deadline of 5 December 2027. Any qualifying organisation must carry out a full energy audit and notify the Environment Agency by this date.
Failure to meet this deadline can result in compliance notices, enforcement action and significant financial penalties. Under current regulations, individual fines range from £5,000 to £90,000 depending on the severity of the breach and whether previous deadlines have been missed. These breaches are then aggregated to form a total fine.
In addition to the financial risk, non-compliant companies may be publicly named by the Environment Agency, which could cause serious reputational damage among regulators, investors, and stakeholders. Lastly, the regulator will require you to correct breaches and complete the work in line with the legislation.
Frequently asked questions
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