Energy Auditing - ASHRAE Level I/II Assessments
ASHRAE Level I and Level II energy audits, utility bill analysis, building envelope assessment, HVAC system efficiency evaluation, and energy conservation measure identification.
- Distinguish between ASHRAE Level I, Level II, and Level III energy audits
- Perform utility bill analysis to identify baseline energy consumption and waste
- Evaluate HVAC system efficiency and identify energy conservation measures
- Calculate simple payback and return on investment for energy upgrades
Lesson 1
ASHRAE Energy Audit Levels
The Three Audit Levels
The American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) defines three levels of energy audits, each increasing in depth, cost, and accuracy of savings predictions. As a Master Specialist, you should understand all three levels and be capable of performing Level I and contributing to Level II audits.
ASHRAE Level I - Walk-Through Analysis is a preliminary assessment that identifies no-cost and low-cost energy savings opportunities. It involves a brief site visit, a review of utility bills, and a visual inspection of major energy-consuming systems. The deliverable is a brief report listing potential energy conservation measures (ECMs) with rough estimates of savings. A Level I audit typically takes 4 to 8 hours for a small to mid-size commercial building.
ASHRAE Level II - Energy Survey and Analysis is a detailed assessment that includes a thorough building walk-through, detailed measurements of equipment performance, analysis of building energy consumption patterns, and engineering calculations of savings for each identified ECM. The deliverable is a comprehensive report with detailed cost-benefit analysis. A Level II audit typically takes 40 to 80 hours depending on building size and complexity.
ASHRAE Level III - Detailed Analysis of Capital-Intensive Modifications is an investment-grade audit focused on a specific major project (such as a chiller plant replacement or building envelope upgrade). It includes detailed engineering analysis, energy modeling, and financial projections suitable for securing financing. This level is typically performed by engineering firms.
Level I - Walk-Through
Duration: 4 - 8 hours
Cost: $2,000 - $5,000
Accuracy: +/- 30 to 40%
Output: Brief report, rough savings estimates
Identifies: No-cost and low-cost ECMs
Level II - Energy Survey
Duration: 40 - 80 hours
Cost: $10,000 - $30,000
Accuracy: +/- 10 to 20%
Output: Detailed report with cost-benefit analysis
Identifies: All viable ECMs with payback calculations
Level III - Investment Grade
Duration: 100+ hours
Cost: $30,000 - $100,000+
Accuracy: +/- 5 to 10%
Output: Engineering analysis, energy model, financial projections
Identifies: Specific capital project ROI and financing structure
Utility Bill Analysis
The starting point for any energy audit is utility bill analysis. Collect at least 24 months of electric and gas bills to establish baseline energy consumption and identify patterns. Key metrics to calculate:
Energy Use Intensity (EUI) - Total annual energy consumption divided by building area:
- EUI = Annual energy (kBTU) / Building area (sq ft)
- The national average EUI for a commercial office building is about 85 kBTU/sq ft/year
- A well-performing building targets 50 to 60 kBTU/sq ft/year
Baseload consumption - The minimum monthly energy use (typically the shoulder months of spring and fall). This represents lighting, plug loads, and any 24/7 equipment. Subtracting the baseload from peak months gives you the weather-dependent consumption attributable to heating and cooling.
Demand charges - Commercial electric bills include demand charges based on the peak 15-minute kW consumption during the billing period. Demand charges can represent 30 to 50% of the total electric bill. Reducing peak demand through load scheduling, demand limiting, and efficiency upgrades can dramatically reduce costs.
ASHRAE defines three energy audit levels with increasing depth and accuracy. Level I is a walk-through that identifies quick wins. Level II provides detailed engineering analysis suitable for budgeting. Utility bill analysis establishes the baseline and identifies weather-dependent vs. baseload consumption. EUI (kBTU/sq ft/year) is the primary metric for comparing building energy performance.