HERS HVAC Systems and Equipment Evaluation Flashcards

What is the purpose of verifying refrigerant charge on a split-system air conditioner during a HERS rating?

Answer: To confirm system efficiency matches rated SEER under actual operating conditions

Improper refrigerant charge reduces system efficiency significantly, so verification confirms the unit performs at its rated SEER.

Which ASHRAE standard governs minimum ventilation rates for residential buildings and is referenced in RESNET HERS ratings?

Answer: ASHRAE 62.2

ASHRAE 62.2 sets minimum mechanical and natural ventilation requirements for low-rise residential buildings.

A HERS rater documents that the home uses a variable-speed air handler. What efficiency advantage does this provide compared to a single-speed unit?

Answer: Lower electricity consumption during part-load operation

Variable-speed air handlers consume significantly less electricity during part-load conditions, which represents the majority of operating hours.

When modeling a home with a dual-fuel heat pump system in REM/Rate, how is the backup heat source typically configured?

Answer: As a separate gas furnace system with its own AFUE

A dual-fuel heat pump pairs an electric heat pump with a gas furnace backup, entered as separate systems with their respective efficiencies.

Under the HERS rating system, which of the following reduces the HERS Index score related to domestic hot water?

Answer: A demand recirculation system with a heat trap

A demand recirculation system with a heat trap reduces standby losses and distribution waste, lowering the hot water HERS score.

Which equipment verification task is specifically required for ENERGY STAR Certified Homes Version 3.2 that goes beyond a standard HERS rating?

Answer: HVAC commissioning by a qualified HVAC contractor using ACCA Manuals J, S, and D

ENERGY STAR V3.2 requires HVAC system design and installation to be verified against ACCA Manuals J, S, and D by a qualified contractor.