--- title: "Energy audit types and audit procedure" subject: "Energy Resources" chapter: 9 key: "semester_6/energy_resources:energy-audit-types-procedure" source: https://www.bctengineer.com/q/semester_6/energy_resources/energy-audit-types-procedure site: BCT Engineering --- # Energy audit types and audit procedure Energy Resources · Chapter 9: Energy audit - Asked in: year not given, 6 marks - Video: [Energy Audit - Need for Energy Audit - Types of Energy Audit](https://www.youtube.com/watch?v=OsJ-j1LHTHk) — Energy Insight Hub (EIH) - Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14 - Page: https://www.bctengineer.com/q/semester_6/energy_resources/energy-audit-types-procedure - Whole chapter: https://www.bctengineer.com/md/semester_6/energy_resources/chapter-9 ## Question What is an energy audit? Differentiate between preliminary (walk-through) and detailed energy audits and describe the steps of a detailed energy audit. ## Short answer An energy audit is a systematic examination of energy use to identify savings opportunities. Preliminary audits are brief (1–3 days), low-cost, with ±20% accuracy; detailed audits involve measurement, energy balances, and costed conservation measures. Steps: planning, walk-through, measurement, analysis, identification of measures, economic evaluation, and reporting with action plan. ## Answer An **energy audit** is a systematic survey and analysis of energy flows in a building, process or plant to find where energy is used, how efficiently, and how much can be saved at what cost. As per the Bureau of Energy Efficiency (BEE) definition, it verifies, monitors and analyses the use of energy and submits a technical report with recommendations. #### Preliminary versus detailed audit | Point | Preliminary (walk-through) | Detailed (comprehensive) | |---|---|---| | Time | 1–3 days | Weeks to months | | Data | Bills, nameplates, observation | Measurements with instruments | | Output | Quick list of no-cost and low-cost savings | Full energy balance and costed projects | | Cost | Low | High | | Accuracy | About ±20 % | About ±5–10 % | #### Steps of a detailed audit 1. **Plan and pre-audit:** define scope, form audit team, collect plant details, process flow, past energy bills (12–36 months), and tariff. 2. **Walk-through survey:** inspect the main users, note obvious wastes and decide where to measure. 3. **Measurement and data collection:** measure electricity, fuel, steam, air, water, temperature and flow of major equipment. 4. **Analysis:** prepare energy balance, specific energy consumption (kWh per unit of product), load profiles, efficiency of equipment, and compare with benchmarks. 5. **Identify energy conservation measures (ECMs):** no-cost (housekeeping), low-cost (maintenance, controls) and high-cost (new equipment). 6. **Economic evaluation:** simple payback = investment ÷ annual saving, net present value and internal rate of return. 7. **Report and presentation** with action plan, then **implementation and follow-up** (monitoring of savings). ## Check yourself The answer's key points as multiple-choice questions, with the correct option and why. 1. What is an energy audit? A. A bill payment check B. A systematic survey and analysis of energy flows to find where energy is used and how much can be saved at what cost C. Installing solar panels D. A tariff negotiation Answer: B. An audit identifies use, efficiency and saving potential. (Key point: Energy audit definition) 2. How does a detailed audit differ from a walk-through audit? A. It uses only bills and observation B. It uses instrument measurements, takes weeks to months, and gives a full energy balance with about +/-5-10 % accuracy C. It takes 1-3 days D. It is less accurate Answer: B. Preliminary audits are quick and about +/-20 %; detailed audits are measured and costed. (Key point: Preliminary vs detailed) 3. Which is the correct order of steps in a detailed audit? A. Report, measurement, planning B. Planning, walk-through, measurement, analysis, ECMs, economic evaluation, report C. Economic evaluation, planning, analysis D. Measurement, report, planning Answer: B. The audit proceeds from plan to survey, data, analysis, measures, economics and report. (Key point: Steps order) 4. How is simple payback calculated? A. Annual saving / investment B. Investment / annual saving C. Investment x annual saving D. Saving - investment Answer: B. Payback in years equals investment divided by annual saving. (Key point: Simple payback) ## Related in Energy Resources - [Energy audit instruments and energy balance](https://www.bctengineer.com/question.md?key=semester_6%2Fenergy_resources%3Aenergy-audit-instruments-measurements) — Energy Resources, chapter 9 - [Preparing and presenting an energy audit report](https://www.bctengineer.com/question.md?key=semester_6%2Fenergy_resources%3Aenergy-audit-report-preparation-presentation) — Energy Resources, chapter 9 - [Energy saving calculation: lighting and motor](https://www.bctengineer.com/question.md?key=semester_6%2Fenergy_resources%3Alighting-motor-energy-saving-case) — Energy Resources, chapter 9 ## Related in other subjects - [Energy audit definition and process](https://www.bctengineer.com/question.md?key=semester_6%2Findustrial_power_distribution_and_illumination%3Adefine-energy-audit-process) — Industrial Power Distribution and Illumination, chapter 10 - [Need of energy audit and technique](https://www.bctengineer.com/question.md?key=semester_6%2Findustrial_power_distribution_and_illumination%3Aenergy-audit-need-technique) — Industrial Power Distribution and Illumination, chapter 10, asked 3× - [Execution phase of energy audit](https://www.bctengineer.com/question.md?key=semester_6%2Findustrial_power_distribution_and_illumination%3Aenergy-audit-execution-phase) — Industrial Power Distribution and Illumination, chapter 10 - [Energy audit technique and saving opportunities](https://www.bctengineer.com/question.md?key=semester_6%2Findustrial_power_distribution_and_illumination%3Aenergy-audit-technique-opportunities) — Industrial Power Distribution and Illumination, chapter 10