ASHRAE Level I vs. Level II vs. Level III Energy Audits Explained

When building owners start looking into commercial energy audits, one of the first questions they ask is: Which ASHRAE energy audit do I actually need?

The answer matters. Choosing the wrong audit level can either leave you with too little information to make decisions or more analysis than your building currently needs.

ASHRAE energy audits are used to evaluate commercial building energy performance, identify energy conservation measures, and guide building owners through the next steps of improving their building.

ASHRAE audit levels generally fall into three categories:

• ASHRAE Level I: Walk-through analysis

• ASHRAE Level II: Energy survey and analysis

• ASHRAE Level III: Detailed analysis of capital-intensive measures, often used for investment-grade decision-making

Each level serves a different purpose. The right choice depends on your goals, building complexity, available data, compliance requirements, and whether you are simply identifying opportunities or preparing to invest in major upgrades.

What Is an ASHRAE Energy Audit?

An ASHRAE energy audit is a structured assessment of how a building uses energy. The audit evaluates major energy-consuming systems and identifies opportunities to reduce energy use.

ASHRAE’s energy audit framework is widely used because it creates a consistent process for evaluating buildings. That consistency matters for owners, managers, and public agencies that need a clear understanding of what an audit should include and what level of analysis is appropriate.

ASHRAE Level I Energy Audit: Walk-Through Analysis

An ASHRAE Level I energy audit is the most basic level of audit. It is often used as a starting point for building owners who want a general understanding of how their building is performing.

A Level I audit typically includes a review of utility data, interviews with building staff when available, and a walk-through inspection of major building systems. The goal is to identify low-cost or no-cost opportunities and determine whether a more detailed audit is warranted.

What a Level I Audit Usually Includes

A Level I audit may include:

• Review of utility bills and energy use trends

• Basic review of building operations

• Walk-through inspection of HVAC, lighting, controls, and other visible systems

• Identification of low-cost and no-cost energy conservation measures

• High-level recommendations for additional investigation

When a Level I Audit Makes Sense

A Level I audit is best when a building owner needs a quick, high-level view of building performance.

It can help answer questions like:

• Is this building using more energy than expected?

• Are there operational issues?

• Are there low-cost improvements we can make quickly?

• Should we invest in a more detailed audit?

A Level I audit can be useful for early-stage planning, but it is usually not detailed enough to support major operational decisions.

ASHRAE Level II Energy Audit: Energy Survey and Analysis

An ASHRAE Level II energy audit provides a more detailed evaluation of building energy use. This is often the most practical audit level for commercial building owners who need actionable recommendations, estimated costs, and projected savings.

Unlike a Level I audit, a Level II audit includes deeper analysis of building systems and energy conservation measures. It typically evaluates specific improvement opportunities and provides financial information to help owners prioritize next steps.

What a Level II Audit Usually Includes

A Level II audit typically includes:

• Detailed utility data analysis

• Review of building operating schedules and occupancy patterns

• Inspection of major energy-consuming systems

• Identification of specific energy conservation measures

• Estimated implementation costs

• Estimated energy and cost savings

• Simple payback calculations

• Prioritized recommendations

The final report should give owners a practical roadmap of what improvements are available, which measures are most cost-effective, and which actions should be considered first.

When a Level II Audit Makes Sense

A Level II audit is appropriate when a building owner needs more than a general assessment.

It is commonly used when:

• A building needs compliance-focused audit documentation

• Ownership is planning capital improvements

• Utility costs are increasing without a clear explanation

• Benchmarking results show poor performance

• The building may need retro-commissioning or system upgrades

• Decision-makers need financial justification for improvements

For many commercial properties, a Level II audit provides the best balance between detail, cost, and actionable recommendations.

ASHRAE Level III Energy Audit: Detailed Analysis for Major Investments

An ASHRAE Level III energy audit is the most detailed level of audit. It is often used when a building owner is considering major capital investments and needs a higher level of analysis before moving forward.

A Level III audit may include more detailed engineering calculations, advanced system analysis, more refined cost estimating, financial modeling, and measurement and verification planning. In some cases, it may also include building energy modeling, depending on the project scope and the decisions being evaluated.

The key difference is that Level III analysis is intended to provide greater confidence for investment decisions involving larger or more complex energy conservation measures.

What a Level III Audit May Include

A Level III audit may include:

• Detailed system-level engineering analysis

• More refined cost estimates

• Life-cycle cost analysis

• Evaluation of capital-intensive retrofit options

• Measurement and verification planning

• Detailed financial analysis

• Energy modeling when appropriate for the project scope

When a Level III Audit Makes Sense

A Level III audit is best suited for complex projects where the financial stakes are higher.

It may be appropriate when:

• You are considering a major HVAC replacement

• You are evaluating deep energy retrofits

• You need investment-grade financial analysis

• A project requires financing or performance contracting

• You need detailed savings projections before committing capital

A Level III audit is not necessary for every building. It is most valuable when the owner needs a high level of confidence before making a major investment.

Which ASHRAE Energy Audit Do You Need?

For most building owners, the decision comes down to intent.

If you are trying to understand whether your building has obvious efficiency opportunities, a Level I audit may be enough.

If you need actionable recommendations, financial analysis, or compliance documentation, a Level II audit is usually the right choice.

If you are preparing for a major capital project and need detailed investment-grade analysis, a Level III audit may be the better fit.

In many cases, the process can be sequential. A building may start with a Level I audit, move into a Level II audit for deeper analysis, and eventually use Level III analysis for a major capital project.

Why ASHRAE Energy Audits Matter for Compliance

Energy audits are becoming more important as cities and states adopt energy benchmarking laws and building performance standards. These policies often require building owners to evaluate energy use, identify improvement measures, and document a plan for reducing energy consumption or emissions.

A properly scoped ASHRAE audit can help owners:

• Understand current building performance

• Identify compliance risks

• Prioritize cost-effective improvements

• Support capital planning

• Prepare for future performance targets

The audit itself does not reduce energy use. It gives owners the information needed to make better decisions. The real value comes from turning audit findings into action.

How IE Energy Helps

IE Energy provides ASHRAE Level I, Level II, and Level III energy audits for commercial, multifamily, and institutional buildings.

Our team helps building owners understand how their buildings use energy, identify practical efficiency opportunities, and develop clear next steps for compliance and performance improvement.

We support:

• Utility data analysis

• Building system inspections

• Energy conservation measure development

• Cost and savings analysis

• Compliance-focused audit documentation

• Long-term energy improvement planning

Our goal is simple: provide clear, actionable audit findings that help building owners make informed decisions and improve building performance.

Start With the Right Audit

Not every building needs the same level of analysis.

The right ASHRAE energy audit depends on where you are in the process: early evaluation, compliance planning, or major capital investment.

IE Energy can help determine which audit level makes sense for your building and provide the analysis needed to move forward with confidence.