HERS HERS HVAC Systems and Equipment Evaluation 2 — Questions and Answers
Question 1: A HERS rater finds duct leakage to outside of 8% of system airflow. Under RESNET standards, how is this reported?
- Pass — within the 10% default allowance (Correct answer)
- Fail — must be below 6% for all homes
- Reported as Total Duct Leakage only
- Reported as QII verified leakage requiring correction
Correct answer: Pass — within the 10% default allowance
RESNET allows a 10% duct leakage to outside default, so 8% passes the verified leakage threshold.
Question 2: What does a high static pressure reading in a forced-air HVAC system indicate to a HERS rater?
- The system is oversized
- There is likely restricted airflow due to undersized ducts or a dirty filter (Correct answer)
- The equipment is operating at peak efficiency
- Duct leakage is within normal range
Correct answer: There is likely restricted airflow due to undersized ducts or a dirty filter
High static pressure indicates restricted airflow, commonly caused by undersized duct work or a clogged air filter.
Question 3: Which fuel source typically yields the lowest HERS Index score (best rating) for space heating in a cold U.S. climate?
- Propane furnace at 96% AFUE
- Natural gas furnace at 95% AFUE
- Air-source heat pump at HSPF 10 (Correct answer)
- Electric resistance baseboard
Correct answer: Air-source heat pump at HSPF 10
A high-efficiency air-source heat pump moves 2–4 units of heat per unit of electricity, delivering a lower HERS Index than combustion heating.
Question 4: During a HERS inspection, a rater verifies that a new home uses an HRV. What is the primary energy benefit of an HRV over exhaust-only ventilation?
- It introduces more fresh air volume
- It recovers heat from exhaust air to pre-condition incoming fresh air (Correct answer)
- It reduces duct leakage to outside
- It eliminates the need for a return air plenum
Correct answer: It recovers heat from exhaust air to pre-condition incoming fresh air
An HRV (Heat Recovery Ventilator) transfers heat from outgoing stale air to incoming fresh air, reducing heating energy loss.
Question 5: A HERS rater is verifying a geothermal heat pump installation. Which performance metric is most relevant for its heating mode efficiency?
- SEER
- AFUE
- COP (Correct answer)
- HSPF
Correct answer: COP
Geothermal (ground-source) heat pump heating efficiency is rated by COP (Coefficient of Performance).
Question 6: Under RESNET HERS standards, what is the Reference Home assumption for water heater efficiency used to calculate the HERS Index?
- EF 0.58 electric storage
- The same equipment as the rated home
- A code-minimum unit based on IECC for the home's location and size (Correct answer)
- A heat pump water heater at UEF 2.0
Correct answer: A code-minimum unit based on IECC for the home's location and size
The Reference Home uses a code-minimum water heater based on IECC requirements for the home's size and climate zone.
HERS HERS HVAC Systems and Equipment Evaluation 2
A HERS rater finds duct leakage to outside of 8% of system airflow.
Under RESNET standards, how is this reported?