BPI Energy Auditing 5 — Questions and Answers
Question 1: A BPI auditor measures 1,200 CFM50 in a 1,500 sq ft single-story home with 8-ft ceilings. What is the ACH50?
- 4.0 ACH50
- 6.0 ACH50 (Correct answer)
- 8.0 ACH50
- 10.0 ACH50
Correct answer: 6.0 ACH50
ACH50 = (CFM50 × 60) / conditioned volume; volume = 1,500 ft² × 8 ft = 12,000 ft³; ACH50 = (1,200 × 60) / 12,000 = 6.0 ACH50.
Question 2: Which diagnostic tool uses infrared radiation to visualize temperature differences across building surfaces during an energy audit?
- Blower door
- Duct blaster
- Infrared camera (thermographic imaging) (Correct answer)
- Digital manometer
Correct answer: Infrared camera (thermographic imaging)
An infrared camera detects surface temperature variations that can reveal missing insulation, air leaks, moisture intrusion, and thermal bridges.
Question 3: What is the function of a 'sacrificial anode rod' in a water heater, and why is it relevant to energy auditing?
- It ignites the pilot light; relevant because pilot lights waste standby energy
- It prevents tank corrosion; relevant because a failed anode shortens water heater life and increases replacement costs (Correct answer)
- It controls water temperature; relevant for standby loss calculations
- It prevents sediment buildup; relevant only in hard-water climates
Correct answer: It prevents tank corrosion; relevant because a failed anode shortens water heater life and increases replacement costs
A sacrificial anode rod corrodes preferentially to protect the tank; an auditor notes its condition because premature tank failure increases lifecycle energy and replacement costs.
Question 4: When performing a combustion efficiency test on a gas furnace, which measurement is used along with flue gas temperature to calculate steady-state efficiency?
- Static pressure across the heat exchanger
- Percent CO₂ or O₂ in flue gases (Correct answer)
- Gas line pressure at the manifold
- Blower motor amperage draw
Correct answer: Percent CO₂ or O₂ in flue gases
Combustion efficiency is calculated from flue gas temperature and CO₂ (or O₂) percentage using the Orsat or equivalent method to determine excess air and heat loss up the flue.
Question 5: Which of the following best describes 'sensible heat' as distinct from 'latent heat' in HVAC and energy auditing?
- Heat that causes a phase change in moisture without changing temperature
- Heat that changes air temperature without a change in moisture content (Correct answer)
- Heat transferred through radiation rather than convection
- Heat stored in thermal mass materials
Correct answer: Heat that changes air temperature without a change in moisture content
Sensible heat changes the temperature of air or a material, while latent heat changes moisture phase (e.g., evaporation/condensation) without changing temperature.
Question 6: An energy auditor finds elevated CO readings in a home with a sealed combustion boiler. What is the most likely explanation?
- The sealed combustion boiler is producing CO due to cracked heat exchanger
- CO is entering from an attached garage or other source unrelated to the boiler (Correct answer)
- The boiler's direct vent pipe is too long
- Outdoor air intake is too close to the exhaust
Correct answer: CO is entering from an attached garage or other source unrelated to the boiler
Sealed combustion appliances draw combustion air from outside and are unlikely to spill CO indoors; elevated ambient CO most likely originates from another source such as an attached garage or vehicle.
Question 7: What is the primary reason BPI protocols require energy auditors to check for asbestos-containing materials before recommending insulation work in older homes?
- Asbestos improves insulation R-value and should not be disturbed
- Disturbing asbestos-containing materials can release fibers that cause serious lung disease (Correct answer)
- Asbestos insulation is energy-inefficient and must be replaced
- Insurance companies require disclosure but there is no health risk
Correct answer: Disturbing asbestos-containing materials can release fibers that cause serious lung disease
Asbestos fibers released during disturbance of ACMs can cause mesothelioma, asbestosis, and lung cancer; auditors must identify risk before any retrofit work proceeds.
BPI Energy Auditing 5
A BPI auditor measures 1,200 CFM50 in a 1,500 sq ft single-story home with 8-ft ceilings.
What is the ACH50?