Index and Ratings Flashcards

A home receives a HERS Index of 0. What does this indicate?

Answer: The home uses no net energy on an annual basis

A HERS Index of 0 represents a net zero energy home that produces as much energy as it consumes annually.

Which of the following scenarios would most likely INCREASE a home's HERS Index score?

Answer: Increasing duct leakage from 4% to 10%

Increasing duct leakage wastes conditioned air and raises energy consumption, which increases the HERS Index score.

When a HERS rater upgrades a home's insulation from R-11 to R-19 in the walls, what is the expected effect on the HERS Index?

Answer: The HERS Index decreases

Better insulation reduces heat transfer and energy demand, which lowers the HERS Index score.

The HERS reference home is set to an index of 100 and is modeled based on which standard?

Answer: RESNET/ICC 301 standard

The HERS reference home is defined by the RESNET/ICC 301 standard, establishing the baseline for index calculations.

A new home scores a HERS 55 and its neighbor scores a HERS 85. Approximately how much more energy efficient is the first home?

Answer: About 30% more efficient

Each point on the HERS scale represents approximately 1% more or less energy use, so a 30-point difference equals roughly 30% greater efficiency.

What is the primary purpose of the projected HERS rating versus the confirmed HERS rating?

Answer: Projected is issued before construction; confirmed is issued after final inspections and testing

A projected rating is based on design documents before construction, while a confirmed rating is issued after the home is built and tested.

Which component of the HERS rating accounts for mechanical ventilation energy use?

Answer: It is part of the total annual energy consumption factored into the index

Mechanical ventilation energy use is included in the total annual energy consumption calculation that determines the HERS Index.