Certified Energy Auditor (CEA) Exam — Questions and Answers

Question 1: The NEMA design classification of a motor most directly determines which performance characteristic?

Speed-torque and starting current characteristics (Correct answer)
Enclosure type and cooling method
Insulation temperature rating
Motor efficiency class

Correct answer: Speed-torque and starting current characteristics

NEMA design letters (A, B, C, D) define the speed-torque curve shape and locked-rotor current, matching motors to load types.

Question 2: What is the purpose of conducting a 'blower door test' during an energy audit?

To test the performance of exhaust fans in meeting code requirements
To balance supply and return airflows in the HVAC distribution system
To measure the airflow capacity of air handling units
To quantify building envelope air leakage at a standardized pressure differential (Correct answer)

Correct answer: To quantify building envelope air leakage at a standardized pressure differential

A blower door test depressurizes or pressurizes the building to a standard 50 Pa and measures air infiltration rate (ACH50), identifying envelope leakage magnitude and locations.

Question 3: When evaluating a portfolio of energy projects with limited capital, the economically optimal strategy is to:

Fund the project with the longest payback first
Rank projects by SIR and fund the highest-SIR projects first (Correct answer)
Fund only projects with an IRR above 25%
Rank projects by NPV alone and fund top projects until budget is exhausted

Correct answer: Rank projects by SIR and fund the highest-SIR projects first

Ranking by SIR maximizes total present-value savings per dollar invested when capital is constrained, following FEMP and ASTM guidelines.

Question 4: During an energy audit, an auditor measures a wall assembly with R-13 cavity insulation and R-5 continuous exterior insulation. What is the approximate total R-value of the insulation components?

R-8
R-18 (Correct answer)
R-13
R-65

Correct answer: R-18

Thermal resistances in series are additive, so R-13 plus R-5 yields a combined insulation R-value of approximately R-18.

Question 5: A project has an NPV of $0 when discounted at 12%. What does this indicate?

The project payback is 12 years
The project generates no savings
The project's IRR equals exactly 12% (Correct answer)
The project should be rejected

Correct answer: The project's IRR equals exactly 12%

When NPV equals zero at a given discount rate, that rate is by definition the Internal Rate of Return (IRR).

Question 6: A building's blended electricity rate is $0.12/kWh. The peak demand charge is $15/kW-month. An energy project reduces consumption by 50,000 kWh/yr and peak demand by 20 kW. What are total annual savings?

$6,000 — consumption savings only
$3,600 — demand savings only
$12,000 — includes projected escalation
$9,600 — consumption plus demand savings (Correct answer)

Correct answer: $9,600 — consumption plus demand savings

Annual savings = (50,000 kWh × $0.12) + (20 kW × $15/kW-month × 12 months) = $6,000 + $3,600 = $9,600.

Question 7: What is a Solar Renewable Energy Certificate (SREC)?

A utility incentive program that pays a fixed rate per kWh for solar power production
A federal tax credit equal to 30% of the cost of a solar installation
A certification required for solar installers to work on commercial projects
A tradeable certificate representing 1 MWh of electricity generated from solar energy (Correct answer)

Correct answer: A tradeable certificate representing 1 MWh of electricity generated from solar energy

An SREC represents 1 MWh of solar electricity generated and can be sold separately from the electricity itself to utilities needing to meet Renewable Portfolio Standards.

Question 8: What is the approximate rule of thumb for energy savings in a compressed air system for every 2 psi reduction in system pressure?

3% energy savings
1% energy savings (Correct answer)
0.5% energy savings
5% energy savings

Correct answer: 1% energy savings

A commonly accepted rule of thumb is that reducing compressed air pressure by 2 psi saves approximately 1% in compressor energy.

Question 9: An energy auditor is evaluating the performance of a large water-cooled centrifugal chiller. Which of the following metrics is the most common and direct measure of its energy efficiency at full-load conditions?

Energy Efficiency Ratio (EER)
Integrated Part Load Value (IPLV)
Coefficient of Performance (COP)
Kilowatts per ton (kW/ton) (Correct answer)

Correct answer: Kilowatts per ton (kW/ton)

While COP and EER are also valid measures of efficiency, kilowatts per ton (kW/ton) is the standard industry metric for expressing the full-load efficiency of large chillers. It directly relates the electrical input power (kW) to the cooling output (tons of refrigeration). A lower kW/ton value indicates a more efficient chiller. IPLV is a measure of part-load efficiency, not full-load.

Question 10: An auditor is planning a Level II energy audit. Which activity distinguishes it from a Level I audit?

Walking through the facility
Interviewing facility managers
Performing detailed energy use calculations and financial analysis for ECMs (Correct answer)
Reviewing utility bills

Correct answer: Performing detailed energy use calculations and financial analysis for ECMs

A Level II audit goes beyond the walkthrough by conducting detailed engineering calculations and cost-benefit analyses for each identified energy conservation measure.

Question 11: Which document published by ASHRAE provides the standard definitions for audit levels I, II, and III?

ASHRAE Standard 62.1
ASHRAE Guideline 14
ASHRAE Standard 100 and the Procedures for Commercial Building Energy Audits (Correct answer)
ASHRAE Standard 55

Correct answer: ASHRAE Standard 100 and the Procedures for Commercial Building Energy Audits

ASHRAE Standard 100 and the ASHRAE Procedures for Commercial Building Energy Audits define the three audit levels and their associated scope requirements.

Question 12: In a cold climate (heating-dominated), where should the vapor retarder be placed within an exterior wall assembly to be most effective at preventing interstitial condensation?

A vapor retarder is not necessary in cold climates.
On the interior (warm) side of the insulation, just behind the drywall. (Correct answer)
In the middle of the insulation layer.
On the exterior side of the insulation, just behind the cladding.

Correct answer: On the interior (warm) side of the insulation, just behind the drywall.

In cold climates, the interior air is typically warmer and more humid than the outdoor air. This creates a vapor drive from the inside to the outside. To prevent this moisture-laden air from entering the wall cavity and condensing on cold surfaces (like the sheathing), the vapor retarder must be placed on the warm-in-winter side of the insulation.

Question 13: What is the primary limitation of using degree-day analysis for predicting energy consumption in buildings with significant internal heat gains?

Internal gains do not affect energy consumption
Degree days cannot be calculated for warm climates
Degree-day data is not available for commercial buildings
Internal gains shift the balance point, making standard degree days inaccurate (Correct answer)

Correct answer: Internal gains shift the balance point, making standard degree days inaccurate

Significant internal heat gains from equipment, lighting, and occupants lower the effective balance point temperature, causing standard 65 degrees F degree days to overestimate heating needs.

Question 14: What is the primary purpose of establishing an energy baseline during the audit process?

To determine the building's original construction date
To calculate the replacement cost of all mechanical equipment
To provide a reference point for measuring the impact of future energy conservation measures (Correct answer)
To establish the maximum occupancy load for fire safety

Correct answer: To provide a reference point for measuring the impact of future energy conservation measures

An energy baseline serves as the benchmark against which all future energy savings from implemented measures are quantified and verified.

Question 15: When analyzing lighting energy data collected via occupancy sensors and data loggers, what metric helps quantify the savings opportunity from reducing burn hours?

Color rendering index (CRI) of existing lamps
Photometric layout uniformity ratio
Lumen output per watt of installed lighting
Annual operating hours multiplied by installed wattage versus occupied-only operating hours (Correct answer)

Correct answer: Annual operating hours multiplied by installed wattage versus occupied-only operating hours

Comparing actual burn hours against occupancy-only hours reveals how many hours lights run unnecessarily, which directly quantifies kWh savings potential.

Question 16: Which type of insulation failure is most commonly identified during an infrared thermography survey of steam piping?

Pipe wall corrosion
Condensate pump cavitation
Pressure relief valve leakage
Wet or missing insulation causing hot spots (Correct answer)

Correct answer: Wet or missing insulation causing hot spots

Infrared thermography detects hot spots on steam piping that indicate wet or missing insulation, which increases surface heat losses significantly.

Question 17: What does the Solar Heat Gain Coefficient (SHGC) of a window measure?

The window's resistance to conductive heat loss
The fraction of solar radiation admitted through the window (Correct answer)
The UV protection factor of the glazing
The visible light transmittance percentage

Correct answer: The fraction of solar radiation admitted through the window

SHGC measures the fraction of incident solar radiation that passes through a window as heat, with lower values indicating less solar heat gain.

Question 18: Which infiltration measurement technique uses tracer gas to determine building air change rates under natural conditions?

Thermographic infrared scanning
Blower door depressurization test
Duct blaster pressurization test
CO2 tracer gas decay method (Correct answer)

Correct answer: CO2 tracer gas decay method

The tracer gas decay method introduces a measured amount of tracer gas (such as CO2 or SF6) and monitors its concentration decay over time to calculate natural air change rates.

Question 19: When performing duct leakage testing, what does the term 'duct leakage to outside' specifically refer to?

Air leaking from ducts into unconditioned spaces such as attics or crawlspaces (Correct answer)
Total air leakage from all duct connections and joints
Outdoor air entering the duct system through return grilles
Air leaking from ducts into conditioned living spaces

Correct answer: Air leaking from ducts into unconditioned spaces such as attics or crawlspaces

Duct leakage to outside measures only the air that escapes from the duct system into unconditioned spaces, which represents a direct energy loss.

Question 20: A chiller log shows entering condenser water temperature consistently 5°F above design. What analytical step should an auditor take first?

Replace the chiller refrigerant charge
Compare actual vs. design cooling tower performance curves (Correct answer)
Increase condenser pump speed
Reduce chilled water set point

Correct answer: Compare actual vs. design cooling tower performance curves

Elevated condenser water temperature usually indicates cooling tower degradation, so comparing actual vs. design tower performance is the correct diagnostic step.

Question 21: Under ASHRAE 90.1, which control is mandatory for all interior lighting in spaces larger than 5,000 ft²?

Automatic time-switch controls (Correct answer)
Daylight sensors
Occupancy sensors
Manual dimming controls

Correct answer: Automatic time-switch controls

ASHRAE 90.1 requires automatic time-switch or scheduling controls for interior lighting in spaces over 5,000 ft² to ensure lights are turned off after hours.

Question 22: A building automation system (BAS) data point showing 'chiller plant delta-T' refers to:

Temperature difference between outdoor and indoor air
Temperature difference between entering and leaving chilled water (Correct answer)
Supply and return duct temperature difference
Difference in refrigerant suction and discharge temperatures

Correct answer: Temperature difference between entering and leaving chilled water

Chilled water delta-T is the difference between the chilled water return temperature and supply temperature, which indicates how effectively the distribution system is transferring heat.

Question 23: What is the most energy-efficient method to control humidity in a commercial building that currently overcools and reheats air?

Add electric resistance reheat coils at each zone
Lower the chilled water supply temperature
Install a dedicated outdoor air system (DOAS) with energy recovery (Correct answer)
Increase the minimum outdoor air damper position

Correct answer: Install a dedicated outdoor air system (DOAS) with energy recovery

A DOAS with energy recovery handles latent loads separately and efficiently, eliminating the wasteful overcool-and-reheat cycle.

Question 24: What does 'degree-day normalization' accomplish when analyzing a facility's historical energy data?

It converts energy units from kWh to BTU
It calculates the depreciation of HVAC equipment
It normalizes energy costs for inflation
It adjusts energy consumption for variations in outdoor temperature to reveal true usage trends (Correct answer)

Correct answer: It adjusts energy consumption for variations in outdoor temperature to reveal true usage trends

Degree-day normalization removes the influence of weather variation from consumption data, allowing auditors to compare energy use across years with different climates.

Question 25: A facility's energy use intensity (EUI) is 120 kBtu/ft²/yr. The national median for its building type is 80 kBtu/ft²/yr. What does this indicate?

The facility's energy costs are 50% above national average
The facility uses 50% more energy per square foot than the median (Correct answer)
The facility is more energy efficient than average
The facility qualifies for ENERGY STAR certification

Correct answer: The facility uses 50% more energy per square foot than the median

An EUI of 120 vs. a median of 80 means the facility consumes 50% more energy per square foot than the typical building of its type.

Question 26: When presenting the financial viability of an energy project, an auditor calculates the discount rate at which the Net Present Value (NPV) of all cash flows (both positive and negative) from the project equals zero. What financial metric has the auditor calculated?

Savings-to-Investment Ratio (SIR)
Simple Payback Period
Return on Investment (ROI)
Internal Rate of Return (IRR) (Correct answer)

Correct answer: Internal Rate of Return (IRR)

The Internal Rate of Return (IRR) is defined as the discount rate that makes the Net Present Value (NPV) of a project equal to zero. It represents the expected annualized rate of return on an investment and is used to assess the profitability of a project.

Question 27: What is the key difference between an energy audit and an energy assessment as defined in most US energy programs?

Only certified professionals can perform assessments
An audit follows a formal structured methodology with documented deliverables, while an assessment is typically less rigorous (Correct answer)
An assessment is always more comprehensive than an audit
They are identical terms with no distinction

Correct answer: An audit follows a formal structured methodology with documented deliverables, while an assessment is typically less rigorous

In most US program contexts, an energy audit follows ASHRAE or DOE protocols with standardized outputs, while an assessment is a broader, less formally structured review.

Question 28: Which ASTM standard governs the test method for air leakage of building envelopes using a blower door?

ASTM E779 (Correct answer)
ASTM C1363
ASTM C518
ASTM E1186

Correct answer: ASTM E779

ASTM E779 is the standard test method for determining air leakage rate by fan pressurization, which is the basis of blower door testing.

Question 29: What is the primary energy-saving opportunity identified when boiler blowdown heat recovery is implemented?

Reducing feedwater chemical usage
Lowering stack gas temperature
Improving combustion air mixing
Recovering heat from blowdown water to preheat makeup water (Correct answer)

Correct answer: Recovering heat from blowdown water to preheat makeup water

Blowdown heat recovery uses a heat exchanger to transfer thermal energy from hot blowdown water to incoming cold makeup water, reducing fuel consumption.

Question 30: A building's HVAC system uses a pneumatic control system. What is a major energy-efficiency concern with this type of system?

Excessive chilled water consumption
Inability to integrate with DDC systems
Hunting and poor setpoint accuracy increasing energy use (Correct answer)
High electrical demand from the compressor serving the controls

Correct answer: Hunting and poor setpoint accuracy increasing energy use

Pneumatic controls are prone to hunting and calibration drift, leading to wider temperature swings and higher energy consumption compared to direct digital control.

Question 31: What is the function of a drainage plane (weather-resistive barrier) behind cladding on an exterior wall?

Vapor retarder to prevent diffusion
Secondary water control layer that drains bulk water away from the sheathing (Correct answer)
Structural backup for the cladding system
Primary air barrier for envelope tightness

Correct answer: Secondary water control layer that drains bulk water away from the sheathing

The drainage plane, such as housewrap or building paper, acts as a secondary water control layer that directs any bulk water that penetrates the cladding away from moisture-sensitive materials.

Question 32: A performance contract (ESPC) shifts the financial risk of energy savings shortfalls to the:

Building owner
Federal government
Energy Service Company (ESCO) (Correct answer)
Local utility

Correct answer: Energy Service Company (ESCO)

In an Energy Savings Performance Contract, the ESCO guarantees the projected savings and absorbs the financial risk if actual savings fall short.

Question 33: An auditor finds that a chiller's actual COP is 3.2 versus a rated COP of 4.5. What is the most likely cause?

Incorrect thermostat setpoints
Excessive supply air static pressure
Fouled condenser tubes reducing heat rejection (Correct answer)
Oversized condenser water pump

Correct answer: Fouled condenser tubes reducing heat rejection

Fouled or scaled condenser tubes increase condenser water temperature, forcing the chiller to work harder and reducing its actual coefficient of performance.

Question 34: During an electrical audit, an auditor finds that a facility pays for 500 kVAR of reactive power monthly. Installing power factor correction equipment brings the power factor from 0.72 to 0.95. What is the primary financial benefit beyond avoiding reactive power charges?

Reduced real energy consumption (kWh) in all equipment
Reduced current draw, lowering conductor I²R losses and potentially reducing demand charges (Correct answer)
Automatic compliance with ASHRAE 90.1 LPD limits
Elimination of harmonic distortion fees

Correct answer: Reduced current draw, lowering conductor I²R losses and potentially reducing demand charges

Improving power factor reduces line current for the same real power, which decreases I²R resistive losses in conductors and may lower the peak kW demand measured by the utility.

Question 35: Which of the following is the primary energy-saving mechanism when a throttling valve on a centrifugal pump is replaced with a Variable Frequency Drive (VFD) to control flow?

The VFD corrects the motor's power factor, reducing reactive power charges.
The VFD allows the motor to run at a slower, more efficient speed, eliminating the energy wasted across the valve. (Correct answer)
The VFD reduces the motor's inrush current during startup, saving demand charges.
The VFD's internal electronics operate more efficiently than the motor itself.

Correct answer: The VFD allows the motor to run at a slower, more efficient speed, eliminating the energy wasted across the valve.

A throttling valve controls flow by creating a large pressure drop, which wastes the energy used to create that pressure in the first place. A VFD saves energy by slowing down the pump to match the system's flow requirements, which drastically reduces power consumption according to the Affinity Laws. This eliminates the energy that was previously dissipated as heat and pressure drop across the valve.

Question 36: An auditor applies a 3% annual compound fuel escalation rate to a current energy cost of $50,000. What is the projected energy cost at the end of Year 2?

$53,045 (Correct answer)
$56,275
$53,000
$51,500

Correct answer: $53,045

Fuel escalation compounds annually: Year 1 = $50,000 × 1.03 = $51,500; Year 2 = $51,500 × 1.03 = $53,045. Using simple (non-compounded) escalation would underestimate future costs.

Question 37: An auditor identifies an ECM with a high NPV but a 12-year simple payback. How should this be presented to the client?

Report only the NPV to avoid discouraging the client
Exclude it from the report since payback exceeds 5 years
Recommend immediate implementation without financial context
Present both metrics and note the long-term financial benefit versus short-term cash flow impact (Correct answer)

Correct answer: Present both metrics and note the long-term financial benefit versus short-term cash flow impact

Presenting multiple financial metrics gives the client a complete picture, allowing them to weigh long-term value against short-term capital constraints.

Question 38: The Discounted Payback Period (DPP) is always _______ the Simple Payback Period (SPP) for the same project.

Equal to
Shorter than
Unrelated to
Longer than (Correct answer)

Correct answer: Longer than

Discounting reduces the value of future savings, so it takes longer to recover the investment when using DPP versus SPP.

Question 39: When developing an audit work plan, what is the correct sequence for identifying energy conservation measures (ECMs)?

Implement, measure, identify, report
Report, analyze, implement, verify
Measure, implement, identify, prioritize
Identify, analyze, prioritize, report (Correct answer)

Correct answer: Identify, analyze, prioritize, report

The standard ECM workflow is to identify opportunities, analyze their savings potential, prioritize by cost-effectiveness, and then document findings in the audit report.

Question 40: An energy auditor measures a 20°F temperature difference across the supply and return of a chilled water coil. If the design delta-T is 12°F, what does this suggest?

The chiller is operating below its rated capacity
The building load exceeds the system design capacity
The cooling tower is rejecting too much heat
The chilled water flow rate is lower than design, causing excessive temperature drop (Correct answer)

Correct answer: The chilled water flow rate is lower than design, causing excessive temperature drop

A higher-than-design delta-T across a coil indicates reduced water flow, causing each unit of water to absorb more heat than intended.

Question 41: Which of the following is considered a crucial first step in the energy audit process, before conducting the on-site survey?

Performing a blower door test to measure air leakage.
Installing sub-meters on all major equipment.
Calibrating detailed energy simulation models.
Collecting and analyzing historical utility consumption data. (Correct answer)

Correct answer: Collecting and analyzing historical utility consumption data.

Collecting and analyzing historical energy data (typically 12-24 months of utility bills) is a fundamental first step in any energy audit. This preliminary analysis helps the auditor understand the facility's energy consumption patterns, establish a baseline, and identify areas to focus on during the on-site inspection.

Question 42: Which metric is used to evaluate the seasonal cooling efficiency of a central air conditioning system?

COP – Coefficient of Performance
AFUE – Annual Fuel Utilization Efficiency
SEER – Seasonal Energy Efficiency Ratio (Correct answer)
EER – Energy Efficiency Ratio

Correct answer: SEER – Seasonal Energy Efficiency Ratio

SEER (Seasonal Energy Efficiency Ratio) measures total cooling output in BTUs over a typical cooling season divided by total electrical energy consumed in watt-hours. It accounts for varying load conditions, unlike the single-condition EER rating.

Question 43: A facility manager reports that a VAV system's supply air temperature is constant at 55°F year-round. What energy savings opportunity does this represent?

Compressor cycling to maintain supply temperature
Supply air temperature reset based on zone demand (Correct answer)
Chilled water loop delta-T improvement
Economizer lockout optimization

Correct answer: Supply air temperature reset based on zone demand

Resetting supply air temperature upward when zone cooling loads are reduced allows the chiller to operate at higher suction temperatures, saving compressor energy.

Question 44: What is 'fuel price escalation' and why is it important in energy economic analysis?

The cost increase associated with switching fuel types
The rate at which equipment efficiency degrades over time
The projected annual increase in energy prices that affects future savings values (Correct answer)
The penalty utilities charge for peak demand usage

Correct answer: The projected annual increase in energy prices that affects future savings values

Fuel price escalation accounts for anticipated increases in energy costs over time, which increases the real value of future energy savings in an LCC analysis.

Question 45: An ASHRAE Level III (Investment-Grade) energy audit differs from a Level II audit primarily because it:

Includes a visual walk-through of mechanical rooms and the building envelope
Collects utility bills for the most recent 12-month period
Provides detailed engineering calculations and rigorous financial analysis sufficient to justify major capital investment decisions (Correct answer)
Identifies low-cost operational improvements with no supporting cost data

Correct answer: Provides detailed engineering calculations and rigorous financial analysis sufficient to justify major capital investment decisions

A Level III audit produces the high-confidence energy savings projections and detailed financial models that lenders, ownership groups, and performance contracting firms require before committing significant capital.

Question 46: During an energy audit, a thermal bridge in a building envelope is best described as:

An air gap intentionally designed to slow heat conduction in a cavity wall
A duct connection that transfers heat between supply and return plenums
A radiant barrier installed to reflect heat toward the conditioned space
A highly conductive pathway through the insulation layer that bypasses thermal resistance (Correct answer)

Correct answer: A highly conductive pathway through the insulation layer that bypasses thermal resistance

A thermal bridge is a material or assembly (such as a steel stud, concrete column, or window frame) with significantly higher conductivity than surrounding insulation, creating a low-resistance path for heat flow and reducing effective wall R-value.

Question 47: An auditor identifies induction motors running at 60% load as a major reactive power source. Which device placed near the motors would most efficiently correct the power factor locally?

Power factor correction capacitors (Correct answer)
Phase converters
Voltage regulators
Isolation transformers

Correct answer: Power factor correction capacitors

Capacitors installed at or near motor terminals supply reactive power locally, reducing reactive current in the upstream distribution system and improving facility power factor.

Question 48: In a Level II ASHRAE energy audit, what distinguishes it from a Level I audit?

It includes detailed energy calculations and financial analysis of proposed measures (Correct answer)
It focuses exclusively on renewable energy options
It requires full building simulation modeling
It only involves a walkthrough with no quantitative analysis

Correct answer: It includes detailed energy calculations and financial analysis of proposed measures

A Level II ASHRAE audit builds on the Level I walkthrough by adding detailed energy calculations, equipment inventories, and cost-benefit analysis for recommended conservation measures.

Question 49: An energy auditor finds a compressed air system where the compressor unloads frequently. What does this most likely indicate?

System demand is significantly less than compressor capacity (Correct answer)
Inlet air filters are clogged
The pressure relief valve is defective
The compressor is undersized for the load

Correct answer: System demand is significantly less than compressor capacity

Frequent unloading indicates the compressor capacity exceeds actual system demand, causing it to cycle between load and unload states.

Question 50: When calculating the internal rate of return (IRR) for an energy project, what does it mean if the IRR equals the organization's minimum acceptable rate of return (MARR)?

The project generates exactly the minimum required return and is at the threshold of acceptability (Correct answer)
The project's NPV is positive and it should be approved immediately
The project payback period equals the project lifetime in years
The project will generate twice the required return and should be prioritized

Correct answer: The project generates exactly the minimum required return and is at the threshold of acceptability

When IRR equals MARR, NPV equals zero—the project just meets the minimum financial hurdle and the decision is at the breakeven point of acceptability.

Question 51: An auditor collects nameplate data from a rooftop HVAC unit and finds the installed cooling capacity is 60 tons. A peak load calculation for the served zone yields 18 tons. What does this finding most directly indicate?

The equipment is significantly oversized, likely causing short-cycling and degraded efficiency (Correct answer)
The system has appropriate redundancy for a critical cooling application
Additional cooling units should be recommended to handle future load growth
Cooling capacity is adequate and no further analysis is needed

Correct answer: The equipment is significantly oversized, likely causing short-cycling and degraded efficiency

A capacity-to-load ratio of more than 3:1 indicates severe oversizing. Oversized cooling equipment short-cycles — it satisfies the thermostat setpoint quickly and shuts off before completing a full dehumidification cycle — reducing efficiency, increasing wear, and degrading occupant comfort. This is a key finding requiring equipment right-sizing as an energy conservation measure.

Question 52: Which of the following best describes the concept of an energy baseline in audit planning?

A historical reference period of energy use against which future savings are measured (Correct answer)
The rated energy consumption from equipment nameplates
The minimum energy the facility must use to comply with codes
The energy budget approved for the next fiscal year

Correct answer: A historical reference period of energy use against which future savings are measured

An energy baseline represents actual historical consumption, typically 12–36 months of utility data, used as the reference point for calculating post-ECM savings.

Question 53: Which condition should an energy auditor consider before performing a blower door test in a home with combustion appliances?

Interior humidity must be above 30% RH
All duct registers must be sealed before testing
Combustion appliances should be shut off or monitored to prevent backdrafting during depressurization (Correct answer)
Outdoor wind speed must be below 15 mph

Correct answer: Combustion appliances should be shut off or monitored to prevent backdrafting during depressurization

Depressurizing a home can cause combustion appliances to backdraft, spilling dangerous flue gases indoors; appliances should be shut down or carefully monitored during the test.

Question 54: There are 50 employees working in an office building, which is occupied 250 days a year. Each employee is thought to use an average of 1 gallon of hot water per day for hand washing. City water is 60°F while the required hot water temperature is 120°F. Determine the annual energy consumption for heating this water:

12.50 MMBTUs
6.25 MMBtus (Correct answer)
15.4 MMBtus
25 Mbtus

Correct answer: 6.25 MMBtus

To calculate the annual energy consumption, first determine the total annual hot water usage: 50 employees * 1 gallon/day/employee * 250 days/year = 12,500 gallons/year. Using the specific heat of water (8.34 lbs/gallon * 1 Btu/lb°F) and the temperature difference (120°F - 60°F = 60°F), the energy required is 12,500 gallons * 8.34 lbs/gallon * 1 Btu/lb°F * 60°F = 6,255,000 Btu. Converting this to MMBtus (million BTUs) gives approximately 6.25 MMBtus.

Question 55: A compressed air dryer is rated at 500 scfm at 100°F inlet temperature. The actual inlet temperature is 120°F. What happens to the effective drying capacity?

Capacity decreases because warmer air holds more moisture (Correct answer)
Capacity increases due to higher vapor pressure differential
Capacity doubles due to higher thermal energy
Capacity remains the same as temperature is compensated internally

Correct answer: Capacity decreases because warmer air holds more moisture

Higher inlet temperatures increase the moisture load on the dryer, reducing its effective capacity below the rated 500 scfm.

Question 56: Which of the following best describes the shape of an ASHRAE three-parameter (3P) heating changepoint model?

Energy use is constant above a changepoint temperature and increases linearly as temperature falls below it (Correct answer)
Energy use increases linearly with outdoor temperature across all conditions
Energy use is constant below a changepoint temperature and increases linearly as temperature rises above it
Energy use follows a U-shaped curve with minimum consumption at the changepoint temperature

Correct answer: Energy use is constant above a changepoint temperature and increases linearly as temperature falls below it

In a 3P heating model, the building draws only base electrical load when outdoor temperatures are above the heating changepoint. Below that threshold, space heating demand activates and energy use rises linearly as it gets colder. Option C describes a 3P cooling model instead.

Question 57: A $100,000 energy project saves $18,000 per year. Using simple payback, how long will it take to recover the investment?

10 years
5.6 years (Correct answer)
4.5 years
18 years

Correct answer: 5.6 years

Simple payback = $100,000 ÷ $18,000/year ≈ 5.6 years.

Question 58: If $10,000 is invested today at an annual discount rate of 8%, what is its approximate present value in 5 years' time?

$10,000 — present value equals face value
$14,693 — future value, not present value
$6,806 — present value of a future amount (Correct answer)
$8,000 — simple interest result

Correct answer: $6,806 — present value of a future amount

The present value of $10,000 received in 5 years at 8% is PV = 10,000 / (1.08)^5 ≈ $6,806.

Question 59: An energy auditor is performing a Level II audit and finds 15-minute interval electricity data shows demand spikes lasting only 1-2 intervals. What is the most cost-effective first step to address this?

Install a power factor correction capacitor bank at the main panel
Upgrade the utility service to a higher demand tier to reduce penalty rates
Investigate whether the spikes are caused by equipment with staggered start sequencing that could be adjusted (Correct answer)
Install a large battery energy storage system to shave all peaks

Correct answer: Investigate whether the spikes are caused by equipment with staggered start sequencing that could be adjusted

Short-duration demand spikes often result from simultaneous equipment startups; staggering starts through controls or timers can eliminate spikes at minimal cost before capital solutions are considered.

Question 60: The full load rating of a chiller is 0.7 kW/ton. Given that this unit has a 200 ton rating, what is the full load kW?

140 (Correct answer)
75
286
500

Correct answer: 140

The full load kW of a chiller is calculated by multiplying its cooling capacity in tons by its full load rating in kW per ton. In this scenario, a 200-ton chiller with a rating of 0.7 kW/ton requires 0.7 kW/ton * 200 tons = 140 kW. This calculation directly yields the total electrical power consumed when the chiller operates at its maximum capacity.

Question 61: A chiller's efficiency is rated at 0.55 kW/ton. What does this metric directly indicate?

The heat removed per kilowatt-hour of electricity consumed
The seasonal average COP across varying load conditions
The ratio of cooling output to heat rejected at the condenser
The electricity consumed per ton of cooling capacity produced (Correct answer)

Correct answer: The electricity consumed per ton of cooling capacity produced

kW/ton is an efficiency metric for chillers expressing the electrical power input (kilowatts) required to produce one ton (12,000 BTU/hr) of cooling. Lower values indicate higher efficiency.

Question 62: When performing a lighting audit, what does a field-measured 'luminaire dirt depreciation' (LDD) factor below 0.85 suggest?

Fixtures have not been cleaned per the recommended maintenance schedule (Correct answer)
The ballast factor is below specification
Voltage supply to the panel is low
Lamps are near end of rated life

Correct answer: Fixtures have not been cleaned per the recommended maintenance schedule

An LDD below 0.85 indicates significant dust and contamination buildup on luminaires, pointing to inadequate cleaning frequency or missed maintenance cycles.

Question 63: During utility bill analysis, an auditor finds that demand charges account for 48% of a manufacturing facility's monthly electricity costs. Which data collection step should the auditor prioritize next?

Obtain 12 additional months of historical bills to extend the baseline period
Collect interval demand data to identify the timing and sources of peak demand events (Correct answer)
Install sub-meters on the lighting distribution panels
Calculate the building's power factor from nameplate equipment data

Correct answer: Collect interval demand data to identify the timing and sources of peak demand events

When demand charges represent a large share of electricity costs, identifying when and why peak demand spikes occur is the highest-value analytical step. Interval demand data (typically 15-minute readings) reveals which systems or events drive peak demand, enabling targeted load-shedding, load-shifting, or demand-control strategies that can yield significant bill reductions.

Question 64: When energy prices are expected to rise at 3% per year and the discount rate is 8%, what is the real escalation rate to apply to energy costs?

8.0%
5.0% (Correct answer)
11.0%
3.0%

Correct answer: 5.0%

The real escalation rate ≈ (1 + nominal escalation) / (1 + discount rate) − 1 = 1.03/1.08 − 1 ≈ −4.6%, but applying DOE's simplified approach: use the Modified Uniform Present Worth factor with escalation rate e=3% and d=8%, giving an effective real rate of approximately 5% net.

Question 65: In energy auditing, heating degree days (HDD) data is primarily used to:

Determine the minimum outdoor design temperature for equipment sizing
Normalize and compare building energy consumption across different climate years (Correct answer)
Calculate the thermal resistance required for wall insulation
Estimate solar heat gain through south-facing windows

Correct answer: Normalize and compare building energy consumption across different climate years

Heating degree days quantify how cold a location is over time. Auditors use HDD to normalize utility bills across years with different weather, enabling fair comparison of pre- and post-retrofit energy consumption independent of climate variation.

Question 66: During a lighting audit, an energy auditor measures total connected lighting load in a 10,000 sq ft office at 18,000 watts. What is the Lighting Power Density (LPD) in W/sq ft, and how does it compare to the ASHRAE 90.1 office allowance of 1.0 W/sq ft?

1.08 W/sq ft — just above the ASHRAE allowance
18 W/sq ft — 17× the ASHRAE allowance
1.8 W/sq ft — 80% above the ASHRAE allowance (Correct answer)
0.18 W/sq ft — 82% below the ASHRAE allowance

Correct answer: 1.8 W/sq ft — 80% above the ASHRAE allowance

LPD = 18,000 W ÷ 10,000 sq ft = 1.8 W/sq ft. Compared to the ASHRAE 90.1 office allowance of 1.0 W/sq ft, this building uses 80% more lighting power per square foot than the standard permits, indicating a significant opportunity for lighting upgrades.

Question 67: Which instrument is most appropriate for measuring the combustion efficiency of a natural gas boiler during a field audit?

Infrared thermometer pointed at the boiler jacket
Clamp-on ammeter on the burner motor
Portable flue gas analyzer measuring O2 and CO (Correct answer)
Ultrasonic flow meter on the gas supply line

Correct answer: Portable flue gas analyzer measuring O2 and CO

A portable flue gas analyzer measures excess oxygen and carbon monoxide in the flue, which are the primary indicators needed to calculate combustion efficiency.

Question 68: During a building envelope assessment, an auditor finds moisture accumulation inside a wall cavity. Which diagnostic tool is most appropriate to determine the extent of hidden moisture damage?

Digital manometer
Infrared thermography camera
Combustion analyzer
Pin-type moisture meter (Correct answer)

Correct answer: Pin-type moisture meter

A pin-type moisture meter inserted into wall materials provides direct quantitative readings of moisture content within building materials to assess hidden damage.

Question 69: An energy auditor is evaluating two mutually exclusive projects for a client. Project A has a higher Net Present Value (NPV) but a lower Internal Rate of Return (IRR) than Project B. The client's primary goal is to maximize the absolute value added to the company. Which project should the auditor recommend and why?

Neither project, until the payback period for both has been calculated.
Either project, as NPV and IRR are equally valid for this type of decision.
Project B, because its higher IRR indicates a more efficient use of capital.
Project A, because NPV is a direct measure of the total value a project is expected to add. (Correct answer)

Correct answer: Project A, because NPV is a direct measure of the total value a project is expected to add.

When projects are mutually exclusive, the Net Present Value (NPV) is generally the superior decision criterion. NPV calculates the total monetary value a project will add to the firm, which directly aligns with the goal of maximizing value. The Internal Rate of Return (IRR) can be misleading when comparing projects of different scales or cash flow patterns, as it only represents the project's percentage rate of return, not the absolute magnitude of the value created.

Question 70: Property Assessed Clean Energy (PACE) financing is distinctive among energy project funding mechanisms primarily because:

Repayment is attached to the property tax assessment and transfers with the property upon sale (Correct answer)
Repayment terms are limited to a maximum of five years
It can only be used for on-site renewable generation, not efficiency retrofits
It requires a personal credit check and is tied to the individual building owner

Correct answer: Repayment is attached to the property tax assessment and transfers with the property upon sale

PACE financing attaches repayment to the real property rather than the owner, collected through property tax bills. This means the obligation transfers to a new owner at sale and typically allows longer terms (10–25 years), improving project cash flow.

Question 71: Which metric is most commonly used during audit planning to benchmark a building's energy performance against similar facilities?

Peak demand charge (kW)
Annual utility cost per occupant
Energy Use Intensity (EUI) in kBtu/ft²/year (Correct answer)
Total installed equipment nameplate capacity (kW)

Correct answer: Energy Use Intensity (EUI) in kBtu/ft²/year

EUI normalizes energy consumption by floor area and time, allowing meaningful comparison against buildings of the same type regardless of size. It is the standard metric used by tools like ENERGY STAR Portfolio Manager for pre-audit benchmarking.

Question 72: What is the significance of the building envelope's effective R-value compared to the nominal R-value of installed insulation?

The effective R-value is typically higher due to the thermal mass of framing
They are always identical in properly constructed assemblies
The effective R-value is typically lower due to thermal bridging, air leakage, and installation defects (Correct answer)
The effective R-value only applies to commercial buildings

Correct answer: The effective R-value is typically lower due to thermal bridging, air leakage, and installation defects

Thermal bridging through framing, gaps in insulation installation, and air leakage all reduce the actual thermal performance below the nominal R-value printed on the insulation product.

Question 73: A chiller's condenser water leaving temperature is 90°F. Lowering it to 85°F will most likely have what effect on chiller efficiency?

Efficiency decreases due to increased refrigerant flow
No change because chiller kW is fixed
Efficiency decreases due to higher lift
Efficiency improves because condenser pressure drops (Correct answer)

Correct answer: Efficiency improves because condenser pressure drops

Reducing condenser water temperature lowers condensing pressure, reducing compressor work and improving chiller kW/ton.

Question 74: A chiller replacement project has a 15-year economic life. The old chiller has a remaining book value of $20,000. In LCC analysis, how is this treated?

Added to the new project's capital cost
Subtracted from the new system's NPV
Depreciated over the new system's life
Ignored as a sunk cost (Correct answer)

Correct answer: Ignored as a sunk cost

Remaining book value of an existing asset is a sunk cost and does not affect the incremental LCC analysis of the replacement decision.

Question 75: Which metric represents the total annual energy consumption of a building normalized by its floor area?

Annual Fuel Utilization Efficiency (AFUE)
Thermal Conductance Ratio (TCR)
Energy Use Intensity (EUI) (Correct answer)
Building Performance Index (BPI)

Correct answer: Energy Use Intensity (EUI)

Energy Use Intensity (EUI) is expressed in kBtu per square foot per year and allows comparison of energy performance across different-sized buildings.

Question 76: What does an EER rating measure for HVAC cooling equipment that differs from SEER?

EER is used only for geothermal heat pumps
EER measures efficiency at a single peak outdoor temperature condition rather than across a full season (Correct answer)
EER measures heating efficiency while SEER measures cooling efficiency
EER accounts for part-load performance while SEER does not

Correct answer: EER measures efficiency at a single peak outdoor temperature condition rather than across a full season

EER measures cooling efficiency at a single rated condition (typically 95°F outdoor), while SEER averages performance across varying seasonal temperatures.

Question 77: Which thermal imaging condition is most likely to produce accurate results when scanning a building envelope for insulation defects?

When indoor and outdoor temperatures are nearly equal
When there is at least a 10°F temperature difference between indoors and outdoors (Correct answer)
When the HVAC system has been running at maximum capacity for 30 minutes
When the building has been exposed to direct sunlight for several hours

Correct answer: When there is at least a 10°F temperature difference between indoors and outdoors

A minimum temperature differential of approximately 10°F between interior and exterior is needed for infrared thermography to reliably detect insulation voids and thermal bridging.

Question 78: For a tax-paying entity, the after-tax annual savings from an energy project are calculated by:

Subtracting depreciation from gross savings
Adding depreciation tax shield to gross savings
Multiplying gross savings by (1 − marginal tax rate) (Correct answer)
Multiplying gross savings by the marginal tax rate

Correct answer: Multiplying gross savings by (1 − marginal tax rate)

After-tax savings = Gross savings × (1 − tax rate), since energy cost savings increase taxable income and create a tax liability.

Question 79: An energy auditor discovers that a building's chilled water system operates at a constant supply temperature year-round. What energy conservation opportunity does this indicate?

Converting the building to electric resistance heating
Removing all variable frequency drives from pump motors
Replacing the entire chiller plant with air-cooled units
Implementing chilled water supply temperature reset based on outdoor conditions or load (Correct answer)

Correct answer: Implementing chilled water supply temperature reset based on outdoor conditions or load

Chilled water temperature reset raises supply water temperature during low-load conditions, reducing compressor energy consumption while maintaining comfort.

Question 80: For a premium efficiency (IE3) motor versus a standard efficiency motor of the same rating, which statement is generally true regarding motor operating temperature?

IE3 motors run cooler only when oversized by 25%
Operating temperature is identical since rated output is the same
IE3 motors run cooler because they have lower losses (Correct answer)
IE3 motors run hotter due to higher power density

Correct answer: IE3 motors run cooler because they have lower losses

Premium efficiency motors have lower copper, iron, and stray losses, generating less heat and thus running at lower temperatures than standard motors.

Question 81: Measurement and Verification (M&V) costs should be included in a project's economic analysis because:

They are required by state energy codes
They replace the need for engineering estimates
They are always reimbursed by the utility
They are a real project cost that reduces net savings and affects all economic metrics (Correct answer)

Correct answer: They are a real project cost that reduces net savings and affects all economic metrics

M&V costs are legitimate project expenses that reduce net savings and must be included in NPV, IRR, and payback calculations for accurate economic assessment.

Question 82: What is the primary function of a Maximum Power Point Tracker (MPPT) in a PV system?

To regulate battery charging voltage in off-grid systems only
To continuously adjust operating voltage to extract maximum power from PV panels (Correct answer)
To monitor and report peak power output for manufacturer warranty compliance
To prevent the PV system from exceeding the utility interconnection power limit

Correct answer: To continuously adjust operating voltage to extract maximum power from PV panels

An MPPT continuously adjusts the electrical operating point of PV modules to ensure they operate at the voltage-current combination that produces maximum power under varying irradiance and temperature conditions.

Question 83: An energy auditor finds that a building's electricity consumption drops significantly on weekends. This pattern most likely indicates:

Incorrect billing by the utility
A malfunctioning utility meter
Demand response participation by the facility
Process or occupancy-related loads that cease during non-business hours (Correct answer)

Correct answer: Process or occupancy-related loads that cease during non-business hours

Significant weekend consumption drops typically reflect occupancy-driven loads such as lighting, plug loads, and HVAC setback during unoccupied periods.

Question 84: What is the purpose of an interconnection agreement for a grid-tied renewable energy system?

To allow the facility to operate independently from the grid during utility outages
To establish the purchase price the utility will pay for all excess generation
To exempt the facility from demand charges during periods of peak renewable production
To define the technical and safety requirements for connecting the system to the utility grid (Correct answer)

Correct answer: To define the technical and safety requirements for connecting the system to the utility grid

An interconnection agreement establishes the technical, safety, and procedural requirements that must be met before a customer-owned generation system can be connected to the utility distribution grid.

Question 85: A facility manager implemented a large-scale chiller plant optimization project and needs to verify the savings for an ESPC. The project involves multiple interactive system changes, making it difficult to isolate the impact of any single measure. According to the International Performance Measurement and Verification Protocol (IPMVP), which option would be most appropriate for this scenario?

Option A: Retrofit Isolation - Key Parameter Measurement
Option C: Whole Facility (Correct answer)
Option B: Retrofit Isolation - All Parameter Measurement
Option D: Calibrated Simulation

Correct answer: Option C: Whole Facility

IPMVP Option C (Whole Facility) is used when energy conservation measures are expected to have a significant impact on the total energy consumption of the building, or when there are multiple, interactive measures. This method analyzes the energy use of the entire facility using utility meter data before and after the retrofit, making it suitable for complex projects where isolating the savings from individual measures is impractical.

Question 86: During an energy audit, a technician measures lighting levels in an open office at 85 foot-candles (fc). The IES recommended illuminance for that task is 30–50 fc. Which energy conservation measure best addresses this overlighting condition?

Add window films to reduce daylight contribution
Install occupancy sensors on all fixtures
Switch to a higher color temperature lamp to improve perceived brightness
De-lamp or install lower-wattage lamps to reduce installed power density (Correct answer)

Correct answer: De-lamp or install lower-wattage lamps to reduce installed power density

When measured illuminance significantly exceeds the IES recommended level, the most direct fix is reducing installed lighting power — by de-lamping (removing lamps from multi-lamp fixtures) or substituting lower-wattage equivalents. Occupancy sensors address time-of-use waste but do not reduce overlighting while occupants are present. Window film reduces daylight, not electric lighting. Higher color temperature does not reduce energy use.

Question 87: When analyzing a commercial client's utility bills, an energy auditor notices a significant portion of the monthly electricity cost is attributed to a 'demand charge.' What does this charge typically represent?

The total volume of electricity (kWh) consumed during the entire billing period.
A fixed fee for grid maintenance and customer service, regardless of consumption.
A penalty for exceeding a pre-negotiated annual energy budget.
The highest rate of electricity consumption (kW) recorded during a short interval within the billing period. (Correct answer)

Correct answer: The highest rate of electricity consumption (kW) recorded during a short interval within the billing period.

Demand charges are based on the peak rate of energy consumption, measured in kilowatts (kW), during a specific interval (e.g., 15 or 30 minutes) within a billing cycle. This charge compensates the utility for the generation and transmission capacity it must have available to meet the customer's maximum power requirement at any given time, which can be a significant cost component for commercial and industrial customers.

Question 88: An energy auditor calculates the effective whole-wall R-value of an insulated stud-framed wall to be significantly lower than the R-value of the cavity insulation alone. The primary reason for this discrepancy is:

Exterior cladding materials add substantial thermal resistance not accounted for in the cavity R-value
Framing members, headers, and plates act as thermal bridges reducing the assembly's overall R-value (Correct answer)
Cavity insulation degrades over time and loses its rated R-value
Whole-wall R-value calculations include window areas, which have higher insulating values

Correct answer: Framing members, headers, and plates act as thermal bridges reducing the assembly's overall R-value

Wood framing members, top and bottom plates, headers, and corner assemblies have much lower R-values than cavity insulation (roughly R-1.25 per inch vs. R-3.5+ for fiberglass batts). Because studs typically occupy 20–25% of the wall area, they act as thermal bridges that reduce the effective whole-wall R-value well below the nominal cavity insulation value.

Question 89: A facility has a power factor of 0.72. What corrective measure should an energy auditor recommend?

Reduce HVAC supply air temperature
Install variable frequency drives on all motors
Replace fluorescent lamps with LEDs
Add power factor correction capacitors (Correct answer)

Correct answer: Add power factor correction capacitors

Capacitor banks counteract the inductive reactive power from motors and transformers, raising power factor closer to unity and reducing utility demand charges.

Question 90: What is the primary function of an air-side economizer in an HVAC system?

To provide "free cooling" by using cool outside air instead of mechanical refrigeration. (Correct answer)
To increase the humidity of the supply air in dry conditions.
To mix return air with exhaust air before venting to the outside.
To pre-heat ventilation air using exhaust air.

Correct answer: To provide "free cooling" by using cool outside air instead of mechanical refrigeration.

An air-side economizer's main purpose is to reduce the need for energy-intensive mechanical cooling (compressors/chillers) by using cool, low-humidity outdoor air when conditions are favorable. This practice is often called "free cooling." Heat recovery ventilators pre-heat air, and humidifiers add humidity; these are different system components.

Question 91: What is the main advantage of using an electrical sub-meter during an energy audit compared to relying solely on utility bills?

It isolates energy use by system or end-use for precise savings calculations (Correct answer)
It measures fuel combustion efficiency
It automatically adjusts for weather normalization
It eliminates the need for equipment nameplate data

Correct answer: It isolates energy use by system or end-use for precise savings calculations

Sub-metering disaggregates total building energy into end-uses (lighting, HVAC, plug loads), enabling auditors to target the highest-impact measures accurately.

Question 92: A facility replaces a standard efficiency motor (90% efficient) with a premium efficiency motor (95% efficient) rated at 50 hp. Approximately how many kW does the premium motor save at full load?

5.85 kW
3.93 kW
7.46 kW
1.97 kW (Correct answer)

Correct answer: 1.97 kW

Power saved = 50 hp × 0.746 kW/hp × (1/0.90 − 1/0.95) ≈ 1.97 kW.

Question 93: An auditor finds that a 50-hp supply fan motor runs 8,760 hours/year at full speed. Installing a VFD that reduces average speed to 80% would reduce annual kWh consumption by approximately how much?

20%
36%
51% (Correct answer)
49%

Correct answer: 51%

By the cube law, power at 80% speed = 0.8³ = 0.512, so energy savings ≈ 1 – 0.512 = 48.8%, approximately 51%.

Question 94: A Cumulative Sum (CUSUM) chart is applied to a building's monthly energy data after establishing a baseline regression model. What is the primary analytical purpose of this technique?

To determine the optimal independent variable for a regression equation
To compute the building's Energy Use Intensity on a monthly basis
To detect persistent shifts in energy consumption relative to the baseline model (Correct answer)
To calculate the net present value of energy conservation measures

Correct answer: To detect persistent shifts in energy consumption relative to the baseline model

CUSUM accumulates deviations between actual and predicted energy use over time. A sustained upward or downward slope signals a persistent change in energy behavior — such as an equipment malfunction or a successful retrofit — that would be masked in a standard time-series plot.

Question 95: An energy auditor is preparing for an on-site visit to a large, complex manufacturing plant. To ensure the visit is as efficient and productive as possible, which set of documents is most critical to obtain and review beforehand?

The maintenance department's staff vacation schedule.
The company's annual financial statements and marketing materials.
Architectural drawings, major equipment lists with specifications, and production schedules. (Correct answer)
The facility's property tax and insurance records.

Correct answer: Architectural drawings, major equipment lists with specifications, and production schedules.

Reviewing building plans, equipment lists, and operating/production schedules before the visit is crucial for effective planning. [10, 14] This information allows the auditor to understand the facility's layout, identify key energy-consuming systems, and plan the on-site data collection and measurement strategy to align with the plant's operational patterns, maximizing the effectiveness of the time spent on-site.

Question 96: When evaluating a small wind turbine for a facility, what is the generally accepted minimum average annual wind speed for a viable installation?

3 m/s (6.7 mph)
5 m/s (11.2 mph) (Correct answer)
8 m/s (17.9 mph)
10 m/s (22.4 mph)

Correct answer: 5 m/s (11.2 mph)

An average annual wind speed of approximately 5 m/s (about 11 mph) is the generally accepted minimum threshold for a cost-effective small wind turbine installation.

Question 97: What is the purpose of a cooling tower bypass valve in a chilled water plant?

Prevent freezing of cooling tower fill in cold weather (Correct answer)
Increase condenser water flow during peak load
Reduce chilled water pump head pressure
Maintain refrigerant subcooling

Correct answer: Prevent freezing of cooling tower fill in cold weather

A bypass valve diverts warm condenser water around the cooling tower during cold weather to prevent the tower from freezing and to maintain minimum condenser water temperatures.

Question 98: A duct leakage test (duct blaster) measures CFM25 at 25 Pascals of pressure. This value is typically expressed as a percentage of what reference quantity to assess duct system performance?

Outdoor air design flow rate
Return-air grille free area
Total system airflow or conditioned floor area (Correct answer)
Supply plenum static pressure

Correct answer: Total system airflow or conditioned floor area

CFM25 leakage is normalized to total system airflow (CFM_total) or conditioned floor area to yield a leakage percentage or CFM25 per 100 sq ft, allowing comparison across systems of different sizes.

Question 99: During an HVAC system assessment, an auditor measures the chilled water supply temperature at 44°F and the return temperature at 50°F, resulting in a 6°F delta-T. The system was designed for a 12°F delta-T. Which of the following is a likely cause of this "low delta-T syndrome," and what is its primary energy impact?

Cause: The outdoor air economizer is stuck open; Impact: Increased load on the cooling coil, but improved delta-T.
Cause: Oversized chilled water pumps or control valves failing open; Impact: Decreased plant efficiency due to higher pumping energy and inefficient chiller loading. (Correct answer)
Cause: A faulty cooling tower fan; Impact: Increased chiller head pressure.
Cause: Clogged air filters on the air handling unit; Impact: Reduced airflow, but improved chiller efficiency.

Correct answer: Cause: Oversized chilled water pumps or control valves failing open; Impact: Decreased plant efficiency due to higher pumping energy and inefficient chiller loading.

Low delta-T syndrome is often caused by chilled water flowing too quickly through the cooling coils, not allowing enough time for proper heat transfer. This is a common result of oversized pumps or control valves failing open. It forces more water to be pumped than necessary (wasting pump energy) and can cause chillers to run inefficiently at low loads or require more chillers to be staged on to meet the flow demand.

Question 100: What is meant by the term 'specific power' of a compressor as used in energy auditing?

Watts per RPM of shaft speed
Horsepower per cubic foot of compressor volume
kW per 100 scfm of compressed air delivered (Correct answer)
BTU/hr per ton of refrigeration equivalent

Correct answer: kW per 100 scfm of compressed air delivered

Specific power (kW/100 scfm) is the standard metric for comparing compressor efficiency and system performance.

Certified Energy Auditor (CEA) Exam

The Certified Energy Auditor (CEA) Exam exam validates essential knowledge and skills required for certification or licensure in this field.

100

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120 min

Time Limit

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