An In-Depth Guide to Commercial Energy Audits

Energy is one of the highest running costs on a commercial estate, and a commercial energy audit is the usual first step towards bringing it down. A good one gives you a baseline and a ranked list of fixes, and a wireless energy management system keeps those important savings in place.

In this guide, we will cover exactly what a commercial energy audit involves, and how you should act on those results. 

What is a commercial energy audit?

A commercial energy audit is a structured review of how a non-domestic building or estate uses energy. An auditor sets a baseline from your bills and half-hourly meter data, then inspects plant and controls onsite, and the report ranks the measures they find by payback period. You might also see this called a business energy audit, the term means the same thing.

Organisations will usually commission one for one of two reasons:

• To cut costs and carbon - a voluntary audit to find waste and prioritise investment 

• To comply - a mandatory assessment for large UK organisations under ESOS

The output is the same either way, you get a picture of where your energy goes and a list of ways to use it less. 

Types of commercial energy audits 

Most commercial energy audits fall into one of three types, depending on how deeply the auditor measures your buildings:

• Walkthrough audit - The auditor visits the site and reviews your bills, then estimates where you could save. It is quick and low cost, and works well for screening sites across a portfolio. 

• Detailed audit - The auditor fits meters or data loggers, so each saving comes from measured data. This costs more, and gives you figures you can base your budget on. 

• Targeted audit - The auditor examines one system in depth, such as refrigeration or HVAC. This type of audit suits an estate that has already traced a problem to that system. 

You can start with a walkthrough and use the findings to decide whether a more detailed audit is needed. Many multi-site estates do this, a walkthrough at each site to rank them, then a more detailed audit at the highest consumers. 

What happens during a commercial energy audit 

Most commercial energy audits move through four stages. These include: 

1. Prepare

To start with, agree what you want from the audit before anyone visits. A measurable goal, such as a percentage cut in energy cost, helps to give the auditor a target. Bring in the finance lead who approves spend and the site managers who run the buildings, because both will need to act on the findings.

Then it’s time to gather your data. Use this energy audit checklist:

• 12 to 24 months of energy bills and half-hourly meter data

• Floor plans and an asset list for main plant 

• BMS access, or a record of current schedules and setpoints

• Maintenance logs and any previous audit reports

• Opening hours 

The less the auditor has to estimate, the more you can rely on the savings figures.

2. The site visit

The auditor walks the site and inspects your plant and controls, then the building fabric. They spend the most time on HVAC, since it accounts for the majority of energy use in a typical commercial building. 

• Plant and controls - the auditor checks the condition of your heating, cooling, hot water and refrigeration systems, and whether schedules match how you use the building.

• Lighting and small power - the auditor will review lighting controls and have a look for anything left running out of hours 

• Building fabric - They inspect insulation and air leakage. 

• People - The auditor also interviews site managers and staff, who know which systems get overridden and which rooms sit empty.

Auditors will use thermal imaging to find air leaks and insulation gaps. A detailed audit adds clip-on loggers that record how equipment draws power over several weeks. 

3. Analyse the data 

Back at the desk, the auditor sets your baseline from 12 to 24 months of consumption and uses half-hourly data to separate out-of-hours use from the occupied day. If you run several sites, they benchmark them against each other. They will then put a cost and a payback period against each measure.

4. Review the report 

A good report has four parts:

• Consumption breakdown - it shows where your energy goes, by end use and by site. 

• Ranked measures - It ranks each measure and gives an estimated cost and payback period.

• Confidence levels - It states how each saving was calculated, so you can see which figures come from measurement and which from estimates. 

• Action plan - It names an owner and date for each measure. 

Commercial energy audit requirements in the UK 

Large UK organisations must carry one out under the Energy Savings Opportunity Scheme (ESOS), which requires an energy assessment every four years. You qualify if you employ 250 or more people, or if your turnover and balance sheet both exceed the size thresholds on the qualification date. For phase 4, that date is 31st December 2026, and the compliance deadline is 5th December 2027.

A Lead Assessor signs off the assessment. Since phase 3, you also submit an action plan and annual progress updates, so you report on your findings. If one UK company in a corporate group qualifies, the whole UK group takes part. Make sure to check your position against the Environment Agency’s current guidelines. 

Common findings from a commercial energy audit

The same faults tend to turn up across UK commercial estates. These include:

• Out-of-hours consumption - Lighting and HVAC keep running while the building is empty. 

• Outdated schedules - Timers set at commissioning stay unchanged for years, including over bank holidays. 

• Simultaneous heating and cooling - Two systems work against each other in the same space. 

• Setpoint creep - Staff nudge targets up or down over the years, and these stay in place.. 

• Sensor drift - A drifting temperature sensor holds a zone too warm or too cold and doesn't raise an alarm.

• Unmonitored equipment - some assets sit outside the BMS or have no metering, so you can’t see what they use. 

Most estates that act on findings like these cut energy use by 10% to 30%.

What to do with your energy audit results 

An audit is a snapshot of one site visit and a few weeks of data, things can change, so it’s important to make sure you act quickly. 

• Start with the quick fixes - Schedule and setpoint changes need no budget approval, and their savings help fund capital projects.

• Give each action an owner and date - Make sure to assign each measure to a named person with a target date, and review progress at your regular facilities meetings.

• Record a baseline before changing anything - Comparing before and after lets you prove each saving to your finance team.

• Keep monitoring after the audit - A one-off audit gives you no warning when someone overrides a schedule in month four or a compressor starts to fail in month nine. An energy management system covers the gap with continuous monitoring and live alerts.  

Follow these steps and the savings from your audit will stay in place after the auditor has left. 

How Clearworld can help you save money with an energy audit

At Clearworld, we start with your data and end with a plan to act on it in four stages:

• Free data audit - We analyse your half-hourly data to find hidden usage and high-consumption devices, then size the ROI opportunity before anyone visits a site. 

• Pilot sites - We install wireless sensors and controls, called Sense iQ, at pilot sites, so each finding has measured, device-level data behind it.

• Business case - We turn each finding into a line in the business case: the asset, the fault, the fix, the cost and the saving. We calculate ROI from your own data and pilot results.

• Phased roll-out - We roll out in phases to match your budget. Vision iQ runs on a CapEx model, so you own the hardware and pay no subscription. 

Clearworld clients average 19% energy savings and a 12-month payback. 

Our clients manage portfolios from 40 to 850 sites, with most sites going live in a single visit with no rewiring and no downtime. If you already have a BMS, Vision iQ™ bolts on to fill the gaps, so you can act on audit findings your current system can't reach. 

Book a free audit with our team today.

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