ESCO ESCO Commissioning and Retro-Commissioning 2 — Questions and Answers
Question 1: What is 'ongoing commissioning' (also called 'continuous commissioning') in the context of an ESCO performance contract?
- The use of building automation system trend data and analytics to continuously identify and correct operational degradation over time (Correct answer)
- Annual recertification by a third-party commissioning authority
- Monthly manual inspection of all HVAC equipment
- A fixed 5-year recommissioning cycle mandated by the contract
Correct answer: The use of building automation system trend data and analytics to continuously identify and correct operational degradation over time
Ongoing commissioning uses automated monitoring to detect drift in setpoints or sequences, enabling rapid correction before energy waste accumulates.
Question 2: In an ESCO retro-commissioning project, what is an 'economizer lockout setpoint' and why is correcting it important?
- The outdoor air temperature above which the economizer is disabled; an incorrect (too-low) setpoint prevents free cooling and wastes energy (Correct answer)
- The minimum chilled water setpoint for the AHU cooling coil
- The maximum allowable supply air temperature during morning warm-up
- The CO2 threshold that triggers demand-controlled ventilation
Correct answer: The outdoor air temperature above which the economizer is disabled; an incorrect (too-low) setpoint prevents free cooling and wastes energy
A lockout setpoint set too low prevents the economizer from using cool outdoor air for free cooling, forcing the chiller to run unnecessarily.
Question 3: What is 'simultaneous heating and cooling' and why is it a key finding in ESCO commissioning investigations?
- A condition where reheat coils heat air that was just mechanically cooled, wasting both heating and cooling energy (Correct answer)
- A design strategy for thermal comfort in mixed-use spaces
- A dual-fuel system that switches between gas and electric heating
- A control mode used during morning warm-up only
Correct answer: A condition where reheat coils heat air that was just mechanically cooled, wasting both heating and cooling energy
Simultaneous heating and cooling is a major source of energy waste in VAV systems and is one of the highest-value deficiencies RCx corrects.
Question 4: Which tool do commissioning providers most commonly use to analyze BAS trend data for retro-commissioning fault detection?
- Automated Fault Detection and Diagnostics (AFDD) software (Correct answer)
- Portable power quality analyzer
- Duct blower door test equipment
- Refrigerant manifold gauge set
Correct answer: Automated Fault Detection and Diagnostics (AFDD) software
AFDD software parses logged sensor data to automatically flag control anomalies, equipment faults, and energy waste patterns.
Question 5: What is a 'commissioning authority' (CxA) and what is their key independence requirement?
- A qualified professional who leads the commissioning process and must be independent from the design and construction teams to avoid conflicts of interest (Correct answer)
- The building owner's facilities manager who approves all work
- The mechanical contractor responsible for startup and testing
- The local code official who performs final inspections
Correct answer: A qualified professional who leads the commissioning process and must be independent from the design and construction teams to avoid conflicts of interest
Independence ensures the CxA can objectively verify that systems meet the OPR without pressure from designers or contractors to overlook deficiencies.
Question 6: In a typical US commercial ESCO retro-commissioning study, what is the average energy cost savings range as a percentage of total facility energy cost?
- 5–15% (Correct answer)
- 25–40%
- 1–2%
- 50–70%
Correct answer: 5–15%
Industry studies consistently show RCx delivering 5–15% whole-building energy savings with paybacks typically under 3 years.
ESCO ESCO Commissioning and Retro-Commissioning 2
What is 'ongoing commissioning' (also called 'continuous commissioning') in the context of an ESCO performance contract?