HERS Index and Ratings 2 — Questions and Answers
Question 1: A home receives a HERS Index of 0. What does this indicate?
- The home uses no net energy on an annual basis (Correct answer)
- The home is 100% more efficient than the reference home
- The home fails minimum code requirements
- The home has no HVAC system installed
Correct 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.
Question 2: Which of the following scenarios would most likely INCREASE a home's HERS Index score?
- Adding solar photovoltaic panels
- Replacing single-pane windows with double-pane
- Increasing duct leakage from 4% to 10% (Correct answer)
- Upgrading to a higher-efficiency heat pump
Correct answer: Increasing duct leakage from 4% to 10%
Increasing duct leakage wastes conditioned air and raises energy consumption, which increases the HERS Index score.
Question 3: 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?
- The HERS Index increases slightly
- The HERS Index decreases (Correct answer)
- The HERS Index is unaffected by wall insulation
- The HERS Index doubles
Correct answer: The HERS Index decreases
Better insulation reduces heat transfer and energy demand, which lowers the HERS Index score.
Question 4: The HERS reference home is set to an index of 100 and is modeled based on which standard?
- ASHRAE 90.1-2013
- IECC 2006
- RESNET/ICC 301 standard (Correct answer)
- DOE Building America guidelines
Correct answer: RESNET/ICC 301 standard
The HERS reference home is defined by the RESNET/ICC 301 standard, establishing the baseline for index calculations.
Question 5: A new home scores a HERS 55 and its neighbor scores a HERS 85. Approximately how much more energy efficient is the first home?
- About 30% more efficient (Correct answer)
- About 55% more efficient
- About 85% more efficient
- Exactly twice as efficient
Correct 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.
Question 6: What is the primary purpose of the projected HERS rating versus the confirmed HERS rating?
- Projected is used for tax credits; confirmed is used for financing
- Projected is issued before construction; confirmed is issued after final inspections and testing (Correct answer)
- Projected covers HVAC only; confirmed covers the whole building envelope
- Projected applies to existing homes; confirmed applies to new construction only
Correct 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.
Question 7: Which component of the HERS rating accounts for mechanical ventilation energy use?
- It is excluded from HERS calculations entirely
- It is included under the lights and appliances end use
- It is part of the total annual energy consumption factored into the index (Correct answer)
- It is only counted if ventilation airflow exceeds ASHRAE 62.2 minimums
Correct 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.
HERS Index and Ratings 2
A home receives a HERS Index of 0.
What does this indicate?