HERS Index and Ratings 3 — Questions and Answers
Question 1: A HERS rater is evaluating an existing home built in 1985. Which type of HERS rating is most appropriate?
- Projected rating based on blueprints
- Confirmed rating with full field verification and testing (Correct answer)
- Preliminary rating based on county records only
- Design rating with no field inspection required
Correct answer: Confirmed rating with full field verification and testing
Existing homes require a confirmed rating that includes on-site inspection and diagnostic testing to accurately assess actual energy performance.
Question 2: How does the HERS Index treat on-site renewable energy generation such as solar PV?
- It is ignored entirely in the rating
- It reduces the home's energy consumption score, potentially driving the index below 100 (Correct answer)
- It is added to the index as a bonus multiplier
- It only counts if the system is grid-tied and net-metered
Correct answer: It reduces the home's energy consumption score, potentially driving the index below 100
On-site renewable energy offsets the home's consumption, lowering the HERS Index and potentially achieving scores below zero.
Question 3: A home's HERS rating is listed as '52.' Which of the following statements is most accurate?
- The home uses 52% more energy than the reference home
- The home uses 48% less energy than the reference home (Correct answer)
- The home meets 52% of code requirements
- The home has 52 energy-efficient features installed
Correct answer: The home uses 48% less energy than the reference home
A HERS Index of 52 means the home uses 48% less energy than the reference home (which scores 100).
Question 4: Under RESNET standards, which category of energy end use is specifically EXCLUDED from the HERS Index calculation?
- Space heating
- Water heating
- Plug loads and process loads (in some rating types) (Correct answer)
- Cooling
Correct answer: Plug loads and process loads (in some rating types)
Plug loads and process loads are excluded from the standard HERS Index calculation, which focuses on regulated energy end uses.
Question 5: What does a HERS 'sampling' protocol allow a rater to do?
- Rate only one unit in a multi-family building and apply it to all units
- Test a subset of similar homes in a subdivision and apply results to the group (Correct answer)
- Skip duct leakage testing for homes above a HERS 70
- Use projected data instead of confirmed data for new construction
Correct answer: Test a subset of similar homes in a subdivision and apply results to the group
The HERS sampling protocol allows raters to test a representative subset of similar homes in a development and apply those results across the group.
Question 6: A builder asks a HERS rater why their HERS 45 home qualifies for the DOE Zero Energy Ready Home program. What is the best explanation?
- HERS 45 means the home produces more energy than it uses
- The program requires a HERS score at or below 45 for most climate zones (Correct answer)
- HERS 45 automatically qualifies any home as net-zero
- DOE ZERH requires HERS 60 or below, and 45 exceeds that requirement
Correct answer: The program requires a HERS score at or below 45 for most climate zones
The DOE Zero Energy Ready Home program requires a HERS score at or below 45 (varies by climate zone), making a HERS 45 home eligible.
Question 7: How does window-to-floor area ratio affect the HERS Index in a hot climate?
- More window area always improves the HERS Index due to daylighting benefits
- Excessive window area in a hot climate increases cooling loads and raises the HERS Index (Correct answer)
- Window area is not modeled in HERS software
- A higher window ratio always lowers the HERS Index regardless of climate
Correct answer: Excessive window area in a hot climate increases cooling loads and raises the HERS Index
In hot climates, excessive glazing increases solar heat gain, raising cooling energy demand and the HERS Index.
HERS Index and Ratings 3
A HERS rater is evaluating an existing home built in 1985.
Which type of HERS rating is most appropriate?