differences energy audit levels 1 2 3 ashrae commercial building kw engineering

Your Guide to Level 1, 2 & 3 Commercial Energy Audits: Differences Between Cost & Content

Title Image Source: bm4221 from Getty Images via canva.com

What IS the difference is between a Level 1, 2 or 3 ASHRAE energy audit? Which one should I do? How much will it cost? As someone who helped write the book on energy audits and the standard that defines the scope of each, I’d like to help demystify these concepts.

In this post you’ll learn:

• Why there are different audit levels?
• What is the difference between a level 1, 2 and 3 audit?
• How to decide on an energy audit level
• What impacts the cost of an energy audit?
• How to hire a qualified energy auditor
• A bit about targeted audit approaches

Why are there different types of energy audits?

You can conduct an energy audit to varying degrees of depth, and the cost and hence value of that audit will vary too. The idea behind defining audit levels is that one can use them as shorthand for the audit scope. So, if you get bids from two vendors for Level 3 audits, they ought to be comparable. However, this level of detail took a while to define.

When you search for energy audits, you’ll see the name ASHRAE, which is a global organization supporting a sustainable built environment. ASHRAE defined energy audit levels in the first publication of Procedures for Commercial Energy Audits back in 2004. The problem was the original energy audit definitions for Levels 1, 2 and 3 were vague and didn’t go into much detail about scope.

I was the primary author of the second edition of ASHRAE’s publication in 2011, which clarified the level scopes somewhat. But there was still too much room for interpretation to really compare “apples to apples” when bidding audit work.

Then came ASHRAE’s Standard 211 (that I also chaired). It provides a more tightly defined scope and consistent reporting requirements for energy audits. Standard 211 is used by cities around the U.S., and agencies procuring services, to set the scope for energy audits.

What is the difference between audit levels 1, 2 and 3

If you want to get into the nitty gritty of scopes, be sure to check out Standard 211, which lays out the requirements clearly. Here I’ll summarize each level and their key differences. The following diagram provides a nice overview.

energy audit level 1 2 3 differences chart

Key differences between ASHRAE energy audit levels

Benchmarking (aka Preliminary Energy Analysis)

Although benchmarking (defined specifically as Preliminary Energy Use Analysis in Std 211) is not an official level, it is a key step in the audit process and will be found in all levels of energy audits. Benchmarking a building compares its energy use against comparable building stock to examine its operating performance. One of the key metrics for building benchmarking is energy use intensity (EUI), which expresses total building energy use per square foot per year (kBtu/sf/yr).

Level 1

The purpose of a Level 1 energy audit is to identify the rough potential for energy savings in a facility, and it includes benchmarking. A Level 1 audit also includes a list of recommended energy efficiency measures (EEMs), sometimes called energy conservation measures (ECMs), that outlines savings opportunities in the building.

Types of energy efficiency measures

The different types of EEMs are no-cost, low-cost or capital intensive. No-cost or low-cost measures are those that can be done within operating expense budgets (i.e. within the OpEx budget), without significant capital expense that requires more planning (CapEx budget).

  • No-cost measures are projects that have no significant associated cost (except internal labor) and are often operations and maintenance (O&M) changes. These measures reduce energy usage and costs with no capital investment, except for the time and effort of the on-site maintenance personnel.
  • Low-cost measures are projects with relatively small capital outlays. These measures significantly reduce energy consumption and costs while requiring relatively little capital investment.
  • Capital intensive measures are projects with higher capital costs. These measures significantly reduce energy consumption and costs, but also require significant capital investment. “CapEx” projects typically are budgeted a fiscal year in advance.

EEM cost, savings and priorities in a level 1 audit are described as qualitative only (as opposed to quantitative). This means that their exact costs and savings are not required, and are described qualitatively as high, medium, or low. A Level 1 used to be referred to as a “walk-through” audit but that label was dropped in the standard – it’s simply a “Level 1”.

Level 2

A Level 2 energy audit is what most people think of as an “energy audit.” Auditors spend more time on site to speak with facility staff, review drawings not previously provided and perform a detailed building survey.

The Level 2 report includes all of the information from the Level 1, plus a site-specific analysis of recommended EEMs, including expected implementation costs, expected savings, and economics (simple payback or simple ROI).

In addition, the Level 2 includes a summary of the building energy-using systems broken down by end use, its occupancy, historical billing data and observations.

The summary table of a Level 2 is what many owners focus on – the list of recommendations, savings, and economics of each, as shown in the example below.

Scroll to Top