Energy Auditing

Use this page when you need to find where electrical energy is being used, identify avoidable waste, and prove whether changes have reduced consumption.

An electricity energy audit should move beyond bills and meter readings. Those records show how much energy was used, but they do not show which circuits, machines or time periods caused the demand.

Electrocorder loggers record current, voltage, power and energy over time so that the audit is based on measured site behaviour rather than assumptions. The right logger depends on whether you need a full three-phase power study, a single-phase check, a current-only load survey or an appliance-level investigation.

What to measure

• Whole-site or distribution-board load profile over several days or weeks.
• kW, kVA, kVAR, power factor and peak demand where three-phase power analysis is required.
• Current trends on feeders or circuits where a current-only logger is sufficient.
• Single-phase appliance or circuit energy where the question is smaller and more local.
• Before-and-after data to confirm whether energy saving work has made a measurable difference.

Recommended loggers

Product	Logger	Best fit	Measures
	EC-7VAR-RS Electrocorder EC-7VAR-RS Three Phase Voltage, Current & Power Factor Recorder	Best/Purist option for a full three-phase electrical energy audit where voltage, current, power factor, kW, kVA, kVAR and peak demand all matter.	Three-phase voltage, current, power, power factor and energy.
	EC-3A-RS Electrocorder EC-3A-RS Three Phase Current Recorder (400A/3kA)	Useful when the first question is higher-range feeder loading or current trend rather than full power behaviour.	Three-phase current only.
	CT-3A-RS Electrocorder CT-3A-RS Three Phase Current Logger (60A/200A or 60A/400A)	Pragmatic option for three-phase load surveys and long-running current-only checks.	Three-phase current only.
	EC-2VA Electrocorder EC-2VA Power Logger and Energy Recorder	Best for single-phase power and energy checks on circuits or equipment.	Single-phase voltage, current, power and energy.
	CT-2VA Electrocorder CT-2VA Power and Energy Recorder	Best for single-phase current-derived power and energy logging where voltage measurement is not needed.	Single-phase current with estimated voltage for power and energy analysis.
	AL-2VA Electrocorder AL-2VA Energy Logger for Domestic and Light Commercial Appliances	Best for appliance-level checks on domestic or light commercial loads.	Single appliance or socket-level energy use.

Detailed guidance

What is an electricity energy audit?

An electricity energy audit is a measured investigation into where electrical energy is being used, when it is being used, and which loads or circuits offer the best opportunity for savings. The aim is not just to collect data, but to reduce usage in a way that can be checked afterwards.

Most sites already have some useful information available, usually in the form of utility bills, invoices, meter readings and production records. These records are a good starting point because they show historical consumption and cost. What they do not show is where the energy went, which machines or circuits used it, or when the important peaks and base loads occurred. To answer those questions, you need to record data over time with an Electrocorder.

Start with the electrical layout

Before logging data, establish the electrical layout of the site or system being audited. If a wiring diagram or distribution diagram is available, ask a competent electrician or engineer to explain it. If no diagram exists, it may be worth creating a simple one before the audit begins.

The diagram helps identify the main incomers, distribution boards, major circuits and likely access points. It also helps decide whether to start with the total incoming supply, a particular distribution board, or a known high-consumption machine or process.

Purist versus pragmatic measurement

To measure electrical power and energy directly, the purist approach is to measure voltage, current, power factor and time. This is why the EC-7VAR-RS is the best choice for a full three-phase audit: it records voltage and current together, then provides kW, kVA, kVAR, power factor, peak demand and energy information.

For many comparative audits, however, current-only logging can still be a useful and pragmatic approach. Site voltage does vary, but over a normal day or week those variations are often sufficiently cyclic that current trends can still show where demand is coming from and whether a change has reduced load. Current-only logging also avoids a direct voltage connection: the CTs or Rogowski coils are placed around the conductors and the logger records the current profile.

Use the purist route when accurate power, power factor or energy values are required. Use the pragmatic current-only route when the main question is comparative loading, before-and-after current reduction, or identifying which circuit or machine is responsible for demand.

What to record

There are two common ways to carry out the logging work. The first is to start at the top of the electrical system, where the power comes in, and record the total usage profile for a representative period. A week is usually a good minimum because it can include working days, shutdown periods, night load and weekend behaviour. If the site is known to behave the same every day, shorter logging periods may be suitable on individual branches.

After the incoming supply has been recorded, work down through the main circuits, a little like following a family tree. Record the larger branches first, then move towards the loads or machines that appear to be responsible for significant current, power or energy use. This gives a picture of averages, peaks, base load and unusual demand across the site.

Allow enough time for the logging exercise. For example, if the small system shown in the diagram has nine labelled branches and each branch is logged for one day, the minimum logging time would be nine days. A more robust audit may require a week or more on each important branch.

The second approach is to use existing knowledge of the site to go directly to the likely large consumers. If staff already know which machines, processes or circuits are most important, it can be more efficient to start there. In the diagram above, for example, you might log below the 150A branch and compare machines 1, 2 and 3 directly. If machine 3 is taking four times as much current as machines 1 and 2, that quickly tells you where to focus.

Check the results against the bills

Always check the logged results for obvious mistakes. If data is recorded for a representative period, Electrosoft can extrapolate the results and estimate monthly, quarterly and yearly power or energy figures. Compare those figures against the utility bills or meter readings to make sure the scale of the result is credible.

This double-check is especially useful when current-only logging is used, because voltage is being treated as sufficiently stable for the purpose of the comparison. If the estimated figures do not align with the bills, review the logging position, date range, voltage assumptions and site conditions during the test.

Document the audit context

Record where each logger was installed, what circuit or machine it measured, the dates and times of the logging period, and any site context that may explain the data. Weather, production level, shift pattern, shutdowns, maintenance work and unusual business activity can all affect energy use.

A short written summary makes the data much more useful later. It allows the results to be reviewed, repeated, compared with future audits, or used as before-and-after proof when energy saving work has been completed.

How to approach the investigation

• Start with the question: whole-site audit, specific circuit, specific machine, or single appliance.
• Choose a logging period that includes the normal working cycle, weekends, shutdowns or night loads if those affect the site.
• Record enough data to separate base load, process load, peak demand and unusual events.
• Use Electrosoft to review graphs, calculate consumption and compare before-and-after results.

Related guides and products

These pages and products give the next level of detail for this application.

Application guides:

• Energy Audit Loggers: for energy audits, load profiles, peak demand and before/after savings proof.
• Load Survey and Current Loggers: for feeder checks, current logging, load surveys and capacity planning.
• Power Factor and Three Phase Power Loggers: for kW, kVA, kVAR, power factor, peak demand and three-phase power analysis.
• All application guides: choose an Electrocorder by the job or problem you need to investigate.

Relevant products:

• EC-7VAR-RS: Electrocorder EC-7VAR-RS Three Phase Voltage, Current & Power Factor Recorder.
• EC-3A-RS: Electrocorder EC-3A-RS Three Phase Current Recorder (400A/3kA).
• CT-3A-RS: Electrocorder CT-3A-RS Three Phase Current Logger (60A/200A or 60A/400A).
• EC-2VA: Electrocorder EC-2VA Power Logger and Energy Recorder.
• CT-2VA: Electrocorder CT-2VA Power and Energy Recorder.
• AL-2VA: Electrocorder AL-2VA Energy Logger for Domestic and Light Commercial Appliances.