CASE29 · Buildings · ASHRAE Level II audit
Connecting a Level II building audit to nine actionable energy measures
An existing commercial-building audit for a historical LEED-EB submission combines walk-through engineering, BEMS validation, weather analysis and equipment diagnosis with economics and an implementation plan.
01 · CASE ANALYSIS
Audit purpose and scope
The project followed ASHRAE Level II procedures to understand actual system operation and develop an energy-performance implementation plan. Its LEED reference reflects the requirements used at the time of the project.
The investigation covered chillers, cooling towers, AHU/VAV systems, boilers, hot water, lighting and plug loads.
02 · CASE ANALYSIS
Engineering and data validation
Collect utility records, equipment inventories, occupancy and operating schedules; conduct a walk-through and operator interviews; compare BEMS sensors with portable electricity and flow measurements.
Analyze HDD/CDD, hourly to seasonal profiles, part-load COP, load ratio, operating hours and setpoints. Meter quality is checked before estimating improvements.
| Measure | Historical recommendation | Annual potential |
|---|---|---|
| AHU supply-air temperature | Approximately 16–16.5°C → 13°C in cooling mode | 212,353 kWh |
| Economizer limit | Approximately 20.5°C → 16°C | 6,891 kWh |
| Low-load chiller | Smaller unit for shoulder seasons/weekends | 119,774 kWh |
| Warm-up/cool-down | Shorten early-start periods | 43,600 kWh |
| LED lighting | Selected common/support areas | 152,583 kWh |
| Night base load | Stop unnecessary lights/equipment after midnight | 172,463 kWh |
| Boiler operation | Improve load ratio and required-unit staging | 51,215 Nm³ gas |
| Efficient lamps | 32 W → approximately 28 W | 86,766 kWh |
| Occupancy sensors | Restroom lighting | 70,343 kWh |
03 · CASE ANALYSIS
From diagnosis to recommended measures
The nine measures combine air-side setpoint changes, a small chiller for low-load periods, shorter warm-up/cool-down, lighting upgrades, night-load control and boiler staging.
The air-temperature recommendations are project-specific historical measures. They require system and comfort review before transfer to another building.
04 · CASE ANALYSIS
Savings plan and verification
The report targeted 864,772 kWh/year of electricity and 51,215 Nm³/year of gas, equivalent to approximately 7.9% energy reduction when all nine measures are implemented.
Electricity measure values in the source are rounded and their item sum differs from the reported aggregate by 1 kWh; the aggregate is retained rather than silently revised.
| Stage | Output |
|---|---|
| Preliminary audit and walk-through | Energy profile and actual operating issues |
| BEMS validation and performance analysis | Trusted data and system indicators |
| Recommended measures and economics | Nine-measure implementation portfolio |
| M&V and phased execution | Adjusted energy comparison and documented outcomes |
05 · CASE ANALYSIS
Implementation lesson
Define M&V for each measure before execution: fan power and airflow under comparable cooling load, total economizer/chiller energy under adjusted weather, steam-normalized boiler gas and actual lighting hours.
Use economic priorities and low/no-cost versus capital measures to stage implementation. The audit does not establish completed savings or a new certification.
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