Energy Audit Standards

Energy Audits and Auditing Standards

by John A. Herbert, energyLAB

There are essentially three types or levels for an energy audit,  each type would be increasingly more sophisticated, from the simplest to complex:

  1. Walk Through Audit Energy Audit
  2. Standard / Comprehensive Energy Audit
  3. Investment Grade Energy Audit

Primarily the major difference between each is the quantity of data measured and collected.  In turn this impacts the time required to conduct the audit,  the required time for analysis of the data, and therefore the more detailed audit the higher the cost.

Data collected from document analysis and fieldwork is recorded, often on purpose made forms for later analysis.

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Why Audit?

Before getting into the details, it is worth remembering the rational for energy auditing.

The challenges presented by Climate Change alone looms larger everyday, once the tipping point is reached you will be faced with unprecedented demands, add to that resources are indeed finite and dwindling.  Energy security is an issue for nations, but will your business survive the harsh realities of a low carbon economy or succumb? Internationally buildings consume 40% of energy production, in Hong Kong it is 89% accounting for 63% of Hong Kong’s carbon footprint, no wonder government’s are targeting building energy improvements, and the energy audit is the one step to start the process.

An energy audit tracks down waste and uncovers opportunities today to lower your environmental and climate change impacts, it is not in itself a solution, but drives businesses to become aware of the new environment.

Although times have changed, many of the systems essential for the occupation of our building portfolios have never been updated, you wouldn’t run a vehicle without a tune up, the same applies to buildings. Our experts can uncover lost capacity, wasted energy and tune your building for operation today!

Walk-Through Energy Audit

A walk-though energy audit as its name implies involves a walking tour of the premises, where the auditor inspects the energy related systems. Energy data if available for one or more years would be requested for analysis.

Sample readings and measurements are taken, including power, lighting level, thermal comfort are recorded.  EMO (Energy Management Opportunities) and findings are provided in written report for implementation by your management team.


Advantages of the walk-though energy audit include faster results and lower cost. Therefore there is the opportunity to  implement EMO’s faster than the other types of audit. During the audit, the auditor may uncover opportunities that could benefit from a detailed investigation, and the auditor may well recommend a more sophisticated audit for a specific part of a system or process.

Not as sophisticated as a comprehensive energy audit, less data collected and analysed.

Standard Energy Audit

As known as a comprehensive energy audit.  This type of audit involves a more detailed, demanding qualitative and quantitative investigation of the energy systems usage.  If available the historical energy data  for three or more consecutive years is requested for analysis.

This type of audit is not warranted for the majority of installations.

The standard energy audit is more detailed than the walk-through audit,  more data is collected and analysed. Being more through less likely to overlook complex EMO’s.

The standard energy audit takes the auditor more time, data loggers are used to collect additional data – therefore the is more expensive than the walk through audit. Often time consuming data collection is far to too exhaustive to add value.

Investment Grade Energy Audit

The investment grade energy audit is the most sophisticated of all the type of energy audit. It requires detailed energy modelling, analysis of the facility, and energy meter data for several years.

Can be focused for individual systems, most suitable for capital intensive investment programmes.

A very comprehensive energy assessment of the facility and its energy footprint, no stone is left unturned in the search for EMO’s.

Very detailed, but time consuming. The detailed energy modelling and analysis requires many manhours and time to market opportunities may be lost in the process.

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The Energy Audit Report

The resulting output of every energy audit is the report.  This report needs to be a meaningful document comprising the following basic elements:

  1. Information about the energy systems and condition
  2. Fuel usage
  3. Energy usage summary, energy balance with charts
  4. EMO’s  (Opportunities to save money)



There are several guides and standards for energy auditing, the most common include:

  1. Hong Kong Energy Audit Guide
  2. Australian Standard AS/NZ 3598 Energy Audit
  3. ASHRAE Commercial Building Energy Audit Procedures

John Herbert, Consultant