top of page

Commercial Energy Audit Guide: Maximizing Efficiency in Business Facilities


Purpose of the Guide

Welcome to the Commercial Energy Audit Guide. This comprehensive resource aims to educate commercial building owners, facility managers, and other interested stakeholders about the importance, process, and benefits of conducting energy audits in commercial settings. Whether you are seeking to improve your building’s energy efficiency, reduce operational expenses, or move towards sustainable practices, this guide is designed to equip you with the essential knowledge and tools you need to achieve your goals.

The guide offers a step-by-step approach to the energy audit process, from understanding your current energy usage, through conducting various types of audits, to implementing energy conservation measures (ECMs) and verifying their effectiveness. Moreover, it provides information about the tools, techniques, and financial considerations involved in this process, supplemented with case studies to illustrate real-world examples of energy efficiency in action.

Importance of Energy Audits

In today’s world, where energy costs continue to rise and environmental sustainability is a pressing concern, the significance of energy audits cannot be overstated. Commercial buildings account for a substantial portion of the global energy consumption and carbon emissions. Conducting an energy audit helps to identify areas of energy wastage and inefficiency, providing actionable insights to rectify these issues.

Types of Energy Audits

There are three primary types of energy audits, each varying in complexity, detail, and cost:

  1. Walk-Through Audit: Also known as a preliminary audit, this is the most basic type of audit. It involves a simple visual inspection of the building to identify obvious areas of energy waste and suggest quick fixes.

  2. General Energy Audit: This is a more detailed audit that includes a comprehensive analysis of energy consumption data, equipment efficiency, and a cost-benefit analysis of proposed ECMs.

  3. Detailed or Investment-Grade Audit: The most comprehensive type of audit, it includes detailed energy use analysis, advanced data collection and modeling, and a thorough financial analysis of ECMs. This audit is often used when large investments in energy efficiency upgrades are being considered.

Throughout this guide, we will explore each of these audit types in greater detail, providing a roadmap for you to identify which approach is best suited for your specific needs and objectives.

Understanding Commercial Energy Use

Overview of Commercial Energy Use

Commercial buildings, including offices, hospitals, schools, and retail stores, are significant consumers of energy. They use energy for a variety of functions including heating, cooling, lighting, powering equipment, and other operational needs. The energy usage is typically divided amongst various end uses, with HVAC (Heating, Ventilation, and Air Conditioning) systems often accounting for the largest share, followed by lighting, plug loads, and water heating.

The energy consumption in commercial buildings can be influenced by many factors, including the building’s size, location, design, age, type of equipment, and occupancy patterns. Additionally, seasonal variations also impact energy use, with peaks often observed during extreme weather conditions when heating or cooling needs are highest.

Understanding Energy Bills

Understanding your energy bills is the first step towards managing and reducing your energy consumption. Energy bills typically include charges for total energy consumed, demand charges (for the peak amount of energy used at any one time), and sometimes other miscellaneous fees.

The key information to look for in your energy bills includes the billing period, energy rates, total energy consumption, peak demand, and any time-of-use charges. Understanding how your energy use varies across different times of the day, days of the week, and seasons of the year can provide valuable insights into your building’s energy patterns and potential opportunities for savings.

The Role of Energy Efficiency in Commercial Buildings

Energy efficiency plays a crucial role in managing commercial energy use. By improving energy efficiency, commercial buildings can significantly reduce their energy consumption and associated costs, while still maintaining or improving the comfort and productivity of occupants.

Energy efficiency measures can range from simple, low-cost actions, like switching off lights and equipment when not in use, to larger investments like upgrading to high-efficiency HVAC systems or improving building insulation. Not only can these measures reduce operational costs, but they can also enhance building performance, extend the lifespan of equipment, improve indoor air quality, and contribute to environmental sustainability.

In addition, energy efficiency can play a significant role in meeting local, national, and global energy and environmental goals, such as reducing greenhouse gas emissions to combat climate change. Therefore, improving energy efficiency in commercial buildings is a win-win situation for everyone – the building owners, occupants, and the environment.

Preliminary Energy-Use Analysis

1. Gathering Data

The first stage in a preliminary energy-use analysis involves the collection of crucial data about the building and its operations. This typically includes data on energy consumption, building characteristics, and operational and maintenance practices. Energy consumption data can be obtained from utility bills and should ideally span at least one year to capture seasonal variations in energy use.

Data on the building’s physical characteristics includes its size, layout, construction, and the types and specifications of energy-consuming systems installed (like HVAC, lighting, refrigeration, and office equipment). Operational data refers to factors like occupancy hours, set points for heating and cooling systems, and maintenance schedules.

2. Initial Building Survey

After data collection, an initial building survey is performed. This involves a walkthrough of the facility to understand its operations, identify energy-intensive areas, and spot any obvious inefficiencies or malfunctions. For instance, a survey might reveal that a certain area of the building is consistently overheated or that the lighting is not adjusted based on natural daylight availability.

The initial building survey is an excellent opportunity to engage with building occupants, who can often provide valuable insights into the building’s performance and potential issues that might not be evident from the data alone.

3. Analysis of Energy Bills

Energy bill analysis is a critical step in the preliminary energy-use analysis. It involves a detailed review of utility bills over the selected period, allowing auditors to understand energy usage patterns, peak demand periods, and the costs associated with energy consumption.

Different energy users within the facility, such as lighting, HVAC systems, office equipment, and others, will have unique usage patterns that contribute to the overall energy usage profile of the building. Recognizing these patterns and their associated costs helps auditors identify potential areas for energy savings.

The analysis of energy bills can also reveal other important details, such as the rate structure, which can influence the selection and prioritization of energy efficiency measures. For example, if demand charges are a significant component of the energy bill, measures that reduce peak demand might be particularly valuable.

Types of Energy Audits

1. Walk-Through Audit

A walk-through audit, also known as a preliminary or basic audit, is the simplest form of an energy audit. It involves a visual inspection of the building and a review of utility bills to identify glaring inefficiencies and areas for improvement. The auditor generally looks for maintenance issues, inefficiencies, and operational practices that lead to wasteful energy use.

While this type of audit may not provide detailed energy consumption breakdowns or sophisticated energy saving measures, it can often identify “low hanging fruit” or easy-to-implement, cost-effective opportunities for energy savings. These may include replacing outdated lighting fixtures, fixing leaks, optimizing operational schedules, or addressing obvious maintenance issues.

2. General Energy Audit

A general energy audit is more comprehensive than a walk-through audit and provides a detailed overview of how a building consumes energy. It involves an in-depth analysis of utility bills, equipment, operational practices, and occupancy patterns. The audit also includes measurements and calculations to estimate the energy usage breakdown, the efficiency of various systems, and the potential energy savings from proposed energy conservation measures (ECMs).

The general energy audit also provides a financial analysis of the proposed ECMs, including their estimated costs, potential energy savings, and payback periods. This information helps building owners and managers make informed decisions about which ECMs to implement.

3. Detailed (Investment-Grade) Energy Audit

A detailed, or investment-grade, energy audit is the most comprehensive and time-consuming type of energy audit. It provides the most accurate estimate of energy savings and costs associated with the proposed ECMs. This level of audit is typically conducted when a large investment in energy efficiency upgrades is being considered, and precise estimates are required to secure funding.

The investment-grade audit includes detailed energy use simulations, extensive data collection, and advanced engineering analysis. The recommendations from this audit often involve substantial changes, like upgrading HVAC systems, improving insulation, or installing renewable energy systems. A thorough cost-benefit analysis, including life-cycle costs of ECMs, is also a crucial part of this audit.

Each of these audits serves a different purpose and entails a different level of detail and investment. Depending on the building’s needs, one type of audit may be more suitable than the others.

Conducting a Walk-Through Audit

1. Purpose and Scope

A walk-through audit is a basic, preliminary audit aimed at identifying easy-to-implement and often low-cost energy savings opportunities, also known as “quick wins.” This type of audit is a visual inspection of the building that involves a simple survey of its energy-consuming systems and operational practices. The scope typically includes reviewing utility bills, understanding operational and maintenance procedures, and visually inspecting the facility to identify areas of energy waste.

2. Pre-Audit Information Collection

Before the walk-through audit, auditors gather some initial information about the building and its energy use. This typically involves collecting and reviewing utility bills, building plans, and equipment specifications. Additionally, the auditor may conduct an interview with the facility manager or maintenance staff to understand the building’s operational schedule, occupancy patterns, and any known issues or concerns related to energy use.

3. Building Inspection

The building inspection is the main component of the walk-through audit. During the inspection, the auditor visually inspects all energy-related equipment and systems, including HVAC systems, lighting, building envelope, water heating systems, and any other energy-consuming equipment. The auditor looks for areas of potential energy waste, such as unnecessary lighting, poorly maintained equipment, and thermal leaks in the building envelope.

4. Identifying Quick Wins

The final step in a walk-through audit is to identify “quick wins” for energy savings. These are typically low or no-cost measures that can be easily implemented and provide immediate energy savings. They may include actions like adjusting temperature set points, fixing leaks, switching off lights and equipment when not in use, and maintaining equipment for optimal efficiency.

The auditor compiles these measures into a report, detailing the observed inefficiencies, recommended actions, and estimated energy and cost savings. Although a walk-through audit may not provide as detailed analysis or as significant savings as a more comprehensive audit, it is a valuable first step in improving a building’s energy efficiency.

Conducting a General Energy Audit

1. Purpose and Scope

A General Energy Audit offers a more detailed and comprehensive analysis than a basic walk-through audit. It aims to identify all practical measures that could save energy within a facility. The scope of a general energy audit includes a thorough review of utility bills, a detailed building survey, an analysis of energy consumption, and the identification and preliminary financial analysis of Energy Conservation Measures (ECMs).

2. Detailed Energy Consumption Analysis

A key part of a general energy audit is a detailed analysis of the building’s energy consumption. This includes an in-depth review of utility bills to understand energy use patterns, an assessment of the building’s physical characteristics, and an evaluation of its operational and maintenance practices.

The auditor may use data logging equipment to measure the energy use of various systems and equipment in the building, to understand when, where, and how energy is being consumed. This process helps identify inefficiencies that may not be apparent from a simple visual inspection.

3. Identifying Energy Conservation Measures (ECMs)

The goal of a general energy audit is to identify all feasible ECMs. These measures can vary widely in terms of complexity and cost, from simple, low-cost actions like adjusting thermostat settings, to larger investments like upgrading to high-efficiency HVAC systems.

The auditor will typically provide a list of recommended ECMs, along with an explanation of how each measure will reduce energy use and improve the building’s performance.

4. Preliminary Financial Analysis

A preliminary financial analysis is performed for each of the identified ECMs. This involves estimating the costs and benefits associated with each measure, including the upfront investment, annual energy savings, maintenance costs, and the payback period.

This information helps building owners and managers prioritize the recommended ECMs based on their budget, their energy savings goals, and the financial return they expect to achieve. The results of this analysis are compiled into a comprehensive report that forms the basis for decision-making and planning energy efficiency improvements.

Conducting a Detailed Energy Audit

1. Purpose and Scope

A detailed or investment-grade energy audit is the most comprehensive and detailed type of energy audit. It is often performed when a significant investment in energy efficiency upgrades is being considered, and precise estimates are required to secure funding or approval. This type of audit involves a meticulous evaluation of the building’s energy consumption patterns, an in-depth technical and financial analysis of potential Energy Conservation Measures (ECMs), and a comprehensive report detailing the findings and recommendations.

2. Detailed Analysis of ECMs

In a detailed energy audit, each potential ECM is analyzed in depth. This involves a precise calculation of energy savings using advanced tools and techniques, a technical assessment of the measure’s feasibility, and a consideration of its impact on the building’s performance and occupant comfort. This level of detail provides a more accurate and reliable estimate of the expected energy savings, helping building owners and managers make well-informed decisions.

3. Detailed Financial Analysis

The financial analysis in a detailed energy audit is more comprehensive than in less detailed audits. It includes a thorough assessment of the costs and benefits associated with each ECM, including not only the upfront investment and annual energy savings, but also the measure’s impact on maintenance costs, equipment lifespan, and potential incentives or rebates. A detailed financial analysis may also consider the measure’s net present value and internal rate of return, providing a full picture of the financial implications of implementing each ECM.

4. Detailed Audit Report Writing

The detailed audit report is a comprehensive document that presents the findings and recommendations of the energy audit. It typically includes a summary of the building’s current energy consumption patterns, a list of recommended ECMs with detailed technical and financial analyses, and a roadmap for implementing the recommendations. The report may also include appendices with supporting data, calculations, and assumptions.

Energy Audit Tools and Techniques

Various tools and techniques are used in a detailed energy audit to measure and analyze energy consumption and to assess the potential benefits of proposed ECMs. These include:

  1. Energy Use Intensity (EUI): EUI is a metric that normalizes a building’s energy use by its size. It’s calculated as the total energy consumed in one year (in kBtu) divided by the total floor area of the building (in square feet). EUI is a useful metric for comparing the energy efficiency of different buildings or for tracking a building’s energy performance over time.

  2. Benchmarking: Benchmarking involves comparing the building’s energy performance to that of similar buildings. This can help identify whether the building is performing better or worse than expected, indicating potential opportunities for improvement.

  3. Data Logging: Data loggers are devices that record energy use over time. They can be used to track the energy use of specific systems or equipment, providing detailed insights into energy use patterns and identifying inefficiencies.

  4. Thermal Imaging: Thermal cameras can identify areas of heat loss or gain in the building envelope, helping to pinpoint issues like inadequate insulation or air leaks.

  5. Lighting Surveys: A lighting survey involves assessing the existing lighting systems in terms of their energy use, light output, and suitability for the space. This can help identify opportunities for improvements, such as replacing outdated light fixtures with more efficient models or installing controls to reduce lighting use when not needed.

  6. HVAC System Analysis: HVAC systems often account for a significant portion of a building’s energy use, so they are a crucial focus in a detailed energy audit. An HVAC system analysis might include evaluating the efficiency of the system, checking for maintenance issues, and assessing the appropriateness of the system’s size and control settings for the building.

Energy Efficiency Measures

1. Lighting

Efficient lighting systems can significantly reduce energy use in commercial buildings. Measures can include replacing incandescent or fluorescent lamps with energy-efficient LED lights, installing motion sensors or timers to turn off lights when not in use, and maximizing the use of natural daylight through daylight sensors and window treatments.

2. HVAC Systems

HVAC systems often account for a large portion of energy use in commercial buildings. Measures can include upgrading to more efficient heating and cooling equipment, implementing regular maintenance schedules to ensure systems are operating efficiently, installing programmable thermostats to optimize temperature settings based on occupancy and time of day, and optimizing ventilation rates to balance indoor air quality with energy efficiency.

3. Building Envelope

The building envelope – including walls, windows, roofs, and floors – plays a crucial role in maintaining indoor temperatures. Improving insulation, installing energy-efficient windows, and sealing gaps and cracks to reduce air leakage can significantly reduce heating and cooling loads.

4. Water Heating

Energy efficiency measures for water heating can include installing high-efficiency water heaters, insulating hot water pipes, and implementing low-flow fixtures to reduce water consumption.

5. Office Equipment

Energy-efficient office equipment not only consumes less power, but often has a longer lifespan and lower operating costs. Measures can include investing in Energy Star rated devices, implementing power management settings, and encouraging behaviors like turning off equipment when not in use.

6. Industrial Equipment

In industrial settings, improving the efficiency of machinery and processes can lead to significant energy savings. This could involve optimizing the operation of industrial motors, improving process heating and cooling systems, or recovering waste heat.

7. Renewable Energy Options

In addition to reducing energy consumption, commercial buildings can also consider generating their own energy through renewable sources like solar panels, wind turbines, or geothermal systems.

Financing Energy Efficiency Improvements

1. Return on Investment

The return on investment (ROI) is a key factor in deciding whether to implement an energy efficiency measure. It measures the amount of return on an investment relative to the investment’s cost.

2. Payback Period

The payback period is the time it takes for an investment in an energy efficiency measure to be recovered through energy savings. A shorter payback period is generally more desirable.

3. Energy Performance Contracts

Energy Performance Contracts (EPCs) are agreements where the energy savings generated by an energy efficiency project are used to repay the cost of the project over a specified period.

4. Grants and Incentives

Many government agencies and utilities offer grants, rebates, or other incentives to encourage energy efficiency. These can significantly reduce the upfront cost of implementing energy efficiency measures.

Implementing Energy Efficiency Measures

1. Establishing an Energy Management Program

Creating an energy management program involves setting clear goals, allocating resources, and developing an action plan. This may involve appointing an energy manager, setting energy reduction targets, and implementing energy tracking and reporting systems. The program provides a framework for ongoing energy management and ensures accountability and continuous improvement.

2. Project Implementation

Once energy efficiency measures have been identified, a detailed plan is developed to implement these measures. This may involve working with contractors, securing necessary permits, scheduling work to minimize disruption, and communicating with building occupants about what to expect.

3. Staff Training

Staff training is a critical aspect of implementing energy efficiency measures. This can involve training maintenance staff on new equipment or systems, training building occupants on new operational procedures, or providing general education on energy efficiency and conservation.

4. Monitoring and Verification of Energy Savings

Once energy efficiency measures are in place, it’s important to monitor and verify the energy savings. This can involve regular reviews of utility bills, use of energy management software, or more detailed measurement and verification procedures. Regular monitoring ensures that the energy savings are being realized and allows for adjustments to be made if necessary.


This guide to commercial energy audits and energy efficiency is intended to provide a comprehensive overview of the process and benefits of improving energy efficiency in commercial buildings. While the process can be complex, the benefits in terms of cost savings, improved building performance, and environmental sustainability make it a worthwhile investment. With the right approach, any commercial building can become more energy-efficient and contribute to a sustainable future.

If you’re passionate about sustainable living and green technologies, don’t miss the chance to expand your knowledge and contribute to a greener future. Explore our diverse range of books on renewable energy and environmental conservation. Click here to start your journey towards sustainable knowledge today!

Learn more about going solar by clicking the following links:

6 views0 comments


bottom of page