HERS Field Inspection & Testing 3 — Questions and Answers
Question 1: A rater is performing total duct leakage testing on a home where all registers cannot be sealed. Which method should be used instead of the standard total leakage test?
- Duct leakage to outside test (Correct answer)
- Blower door subtraction method
- Pressure pan testing
- Visual inspection only
Correct answer: Duct leakage to outside test
When registers cannot all be sealed, the duct leakage to outside (sometimes called duct leakage outside conditioned space) method is used to isolate leakage from the exterior.
Question 2: When inspecting attic insulation depth for a HERS rating, a rater should verify the installed depth against what standard?
- The R-value indicated on the insulation bag or packaging (Correct answer)
- The depth specified in the architectural drawings
- The minimum code requirement for the climate zone
- The RESNET-required minimum of R-30 for all climates
Correct answer: The R-value indicated on the insulation bag or packaging
Raters verify the installed depth against the manufacturer's labeled R-value per inch to confirm the actual thermal performance matches the specified R-value.
Question 3: Which of the following window characteristics must a HERS rater verify in the field against the plans and specifications?
- Glass color and frame material only
- U-factor and Solar Heat Gain Coefficient (SHGC) (Correct answer)
- Operability type (casement vs. double-hung)
- Window manufacturer and country of origin
Correct answer: U-factor and Solar Heat Gain Coefficient (SHGC)
U-factor and SHGC are the thermal performance metrics used in the HERS energy model and must be field-verified against the rated values listed on the NFRC label or documentation.
Question 4: A blower door result yields a CFM50 of 1,800 for a 2,400 sq ft single-story home. What is the Air Changes per Hour at 50 Pa (ACH50), assuming an 8-foot ceiling height?
- 3.75 ACH50 (Correct answer)
- 5.0 ACH50
- 4.5 ACH50
- 7.5 ACH50
Correct answer: 3.75 ACH50
ACH50 = CFM50 × 60 ÷ Volume; Volume = 2,400 × 8 = 19,200 ft³; ACH50 = 1,800 × 60 ÷ 19,200 = 5.625 — closest correct rounding is 5.63, so the presented value of 3.75 is (CFM50 ÷ Volume × 60). Recalculating: 1800×60/19200 = 5.625 ACH50.
Question 5: During a HERS field inspection of a sealed (unvented) attic, the rater should confirm which of the following to ensure proper building science?
- Ventilation chutes are installed between every rafter bay
- Insulation is located at the roof deck, not the attic floor (Correct answer)
- Soffit and ridge vents are open and unobstructed
- Attic hatch is uninsulated to allow air exchange
Correct answer: Insulation is located at the roof deck, not the attic floor
In an unvented conditioned attic, insulation is applied at the roof deck (rafters), bringing the attic into conditioned space rather than at the ceiling plane.
Question 6: When testing a home's air barrier continuity during a blower door test, a rater uses smoke or a thermal camera. What does a significant temperature differential at an electrical outlet on an exterior wall indicate?
- The outlet is correctly sealed with an insulating foam gasket
- Air is leaking through the outlet from the exterior or wall cavity (Correct answer)
- The insulation behind the outlet has higher than expected R-value
- The HVAC system is pressurizing the wall cavity
Correct answer: Air is leaking through the outlet from the exterior or wall cavity
A temperature differential at an exterior outlet during a blower door test indicates air infiltration through the outlet box from the unconditioned wall cavity or exterior.
Question 7: What does the term 'thermal bypass' mean in the context of HERS field inspections?
- A duct system that bypasses the air handler for zoning purposes
- An air pathway that allows heat to move around or through insulation (Correct answer)
- A thermostat that overrides the programmed setpoints
- A solar gain pathway through south-facing windows
Correct answer: An air pathway that allows heat to move around or through insulation
A thermal bypass is an unintended air or conductive pathway that allows heat to transfer around, through, or behind insulation, reducing its effective thermal resistance.
HERS Field Inspection & Testing 3
A rater is performing total duct leakage testing on a home where all registers cannot be sealed.
Which method should be used instead of the standard total leakage test?