HERS HVAC Systems and Equipment Evaluation Flashcards

A HERS rater finds duct leakage to outside of 8% of system airflow. Under RESNET standards, how is this reported?

Answer: Pass — within the 10% default allowance

RESNET allows a 10% duct leakage to outside default, so 8% passes the verified leakage threshold.

What does a high static pressure reading in a forced-air HVAC system indicate to a HERS rater?

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.

Which fuel source typically yields the lowest HERS Index score (best rating) for space heating in a cold U.S. climate?

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.

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?

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.

A HERS rater is verifying a geothermal heat pump installation. Which performance metric is most relevant for its heating mode efficiency?

Answer: COP

Geothermal (ground-source) heat pump heating efficiency is rated by COP (Coefficient of Performance).

Under RESNET HERS standards, what is the Reference Home assumption for water heater efficiency used to calculate the HERS Index?

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.