ASHRAE Level 1 Energy Audit

An ASHRAE Level 1 energy audit, also called a walk through audit or screening audit, is the fastest and least expensive of the three levels defined under ASHRAE Standard 211. It's built to answer one question quickly: does this building have real energy savings potential worth pursuing further.

What a Level 1 Audit Includes

A Level 1 audit typically combines a review of 12 to 24 months of utility bills, a calculation of the building's Energy Use Intensity, a benchmark comparison against similar buildings using a tool like ENERGY STAR Portfolio Manager, and a brief site walk through to observe major systems in action and talk with facility staff. The deliverable is a short report identifying obvious no cost and low cost energy conservation measures, with rough order of magnitude savings estimates, and a recommendation on whether the building warrants a deeper Level 2 study.

What a Level 1 Audit Does Not Include

A Level 1 audit doesn't involve submetering, data logging, detailed engineering calculations, or computer simulation. Savings estimates are order of magnitude, generally accurate to within plus or minus 30% to 50%, not precise enough to support a major capital decision on their own. That imprecision is by design, a Level 1 audit trades accuracy for speed and cost, and is meant to screen, not to finance.

When a Level 1 Audit Is the Right Choice

Level 1 fits a few situations particularly well: screening a large portfolio to identify which buildings deserve a closer look, a due diligence review ahead of a property acquisition, meeting a basic benchmarking ordinance requirement, or evaluating a small or straightforward building where a more detailed audit wouldn't be cost effective. It's also a standard prerequisite for LEED for Existing Buildings certification, and a common starting point for owners who simply haven't looked closely at their building's energy performance before.

Getting the Most Out of One

Because Level 1 relies so heavily on utility data and a short site visit, data quality in energy management matters more than most owners expect. A full 12 months of accurate utility bills, correct floor area, and accurate property use details will produce a meaningfully more useful Level 1 report than one built on estimates and defaults. Increasingly, Level 1 audits are performed with digital tools, drone thermal imaging, remote utility data access, and virtual walkthroughs, which make the screening pass faster and cheaper still, particularly across a multi building portfolio. We cover how that works in our article on digital energy audits.

If a Level 1 audit flags real potential, the next step is a Level 2 energy survey, which builds on the same data with engineering grade savings and payback calculations for the specific measures a Level 1 study can only estimate roughly.