HERS Field Inspection & Testing — Questions and Answers

Question 1: When performing a blower door test, at what reference pressure is the airflow typically measured for HERS rating purposes?

25 Pascals
50 Pascals (Correct answer)
75 Pascals
100 Pascals

Correct answer: 50 Pascals

Blower door tests for HERS ratings are conducted at 50 Pascals (Pa) of depressurization to standardize results across different homes.

Question 2: A rater measures duct leakage to outside on a new construction home and gets 4.5 CFM25 per 100 sq ft of conditioned floor area. Which ENERGY STAR threshold does this result meet?

It exceeds the ENERGY STAR limit of 4 CFM25
It meets the ENERGY STAR Certified Homes limit of 5 CFM25 or less (Correct answer)
It fails because the limit is 3 CFM25
It passes only if total duct leakage is also tested

Correct answer: It meets the ENERGY STAR Certified Homes limit of 5 CFM25 or less

ENERGY STAR Certified Homes Version 3.2 requires duct leakage to outside to be ≤4 CFM25 per 100 sq ft of conditioned floor area for most climate zones, but thresholds vary; at 4.5 it would fail the 4 CFM25 limit but context matters.

Question 3: During a field inspection, the rater finds insulation installed with a visible air gap between the insulation batt and the exterior wall sheathing. How should this be rated?

Grade I — batts are present and adequate
Grade II — minor defects that reduce performance
Grade III — substantial defects requiring remediation (Correct answer)
Not rated — only blown insulation is graded

Correct answer: Grade III — substantial defects requiring remediation

Air gaps between insulation and the sheathing represent a Grade III installation defect because they create thermal bypasses that substantially degrade insulation performance.

Question 4: What is the primary purpose of a duct pressurization test (Duct Blaster) during a HERS field inspection?

To measure the airtightness of the building envelope
To quantify air leakage from the duct system (Correct answer)
To verify static pressure in supply registers
To measure airflow at each supply outlet

Correct answer: To quantify air leakage from the duct system

A duct pressurization test uses a Duct Blaster to pressurize the duct system and measure the total leakage from supply and return ducts.

Question 5: A HERS rater is inspecting a home with a vented crawl space. Which of the following conditions would be a concern for moisture management during field inspection?

Ground cover vapor barrier covers 100% of the soil
Insulation is installed between the floor joists above
The crawl space vents are open year-round
Exposed soil has no ground cover vapor barrier (Correct answer)

Correct answer: Exposed soil has no ground cover vapor barrier

Exposed soil in a crawl space without a vapor barrier allows moisture to evaporate into the crawl space, risking mold, rot, and energy loss.

Question 6: When verifying mechanical ventilation during a HERS field inspection, what should the rater measure to confirm adequate whole-house ventilation?

Thermostat setpoint and run time
Actual airflow (CFM) compared to the ASHRAE 62.2 required rate (Correct answer)
Number of exhaust fans in bathrooms
Filter MERV rating on the air handler

Correct answer: Actual airflow (CFM) compared to the ASHRAE 62.2 required rate

ASHRAE 62.2 defines minimum whole-house ventilation rates, and the rater must measure actual airflow (CFM) to verify the installed system meets those requirements.

Question 7: During a heating system inspection, the rater observes that a gas furnace flue pipe has a visible gap at a joint inside conditioned space. What is the primary concern?

Reduced AFUE efficiency rating
Combustion gases may spill into the living space (Correct answer)
Noise from combustion air intake
Condensation on the exterior of the flue pipe

Correct answer: Combustion gases may spill into the living space

A gap in a gas furnace flue pipe inside conditioned space can allow dangerous combustion gases, including carbon monoxide, to spill into the living area.

Question 8: 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 9: 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 10: 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 11: 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 12: 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 13: 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 14: 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.

Question 15: What is the RESNET-defined minimum sample rate for rater quality assurance (QA) field inspections of new construction ratings performed by a rater trainee?

5% of ratings per year
10% of ratings per year
15% of ratings per year
25% of ratings per year (Correct answer)

Correct answer: 25% of ratings per year

RESNET standards require a 25% QA field inspection rate for rater trainees to ensure proper oversight before full certification.

Question 16: During a duct leakage test, all supply and return registers are taped off, and the system is pressurized to 25 Pa. What does the measured airflow represent?

Leakage to outside only
Total duct leakage including leakage to inside conditioned space (Correct answer)
Return air leakage only
Envelope leakage attributed to duct penetrations

Correct answer: Total duct leakage including leakage to inside conditioned space

With all registers sealed and the duct system pressurized at 25 Pa, the measured airflow represents total duct leakage from all seams, joints, and connections in the system.

Question 17: A rater inspects a home where the air handler is located in the garage. What is the primary concern with this configuration?

Garage temperatures reduce heating and cooling efficiency
Combustion gases and vehicle exhaust can be distributed throughout the home (Correct answer)
The air handler cannot be tested with a Duct Blaster in this location
Garage-located air handlers are prohibited by RESNET standards

Correct answer: Combustion gases and vehicle exhaust can be distributed throughout the home

An air handler in the garage can draw in vehicle exhaust, carbon monoxide, and other combustion pollutants and distribute them into the living space through the duct system.

Question 18: Which RESNET insulation grading level describes batts that are installed with no more than 2% of the surface area having defects such as gaps, voids, or compressions?

Grade I (Correct answer)
Grade II
Grade III
Grade IV

Correct answer: Grade I

Grade I insulation installation means the insulation is properly cut, fitted, and in full contact with all six sides of the cavity with minimal defects (≤2% affected area).

Question 19: When field-verifying a heat pump water heater (HPWH) for a HERS rating, which specification is most critical to confirm against the energy model inputs?

Tank color and brand name
Uniform Energy Factor (UEF) and installation location (Correct answer)
Number of heating elements and tank shape
Water supply temperature at the fixture

Correct answer: Uniform Energy Factor (UEF) and installation location

The Uniform Energy Factor (UEF) directly determines the water heater's energy efficiency in the model, and installation location affects whether heat pump mode can operate efficiently.

Question 20: A rater is testing a home and finds that the blower door result is significantly lower than expected based on the model inputs. What is the most appropriate action?

Accept the result and file the rating as-is
Report the anomaly and verify that all windows, doors, and penetrations were properly closed during testing (Correct answer)
Increase the model's air leakage input to match the test result
Retest using a higher reference pressure to get a more typical result

Correct answer: Report the anomaly and verify that all windows, doors, and penetrations were properly closed during testing

An unexpectedly low blower door result may indicate a testing error such as an open window or door, so the rater must verify all openings were sealed before accepting the result.

Question 21: What does 'effective R-value' account for that nominal R-value does not?

The brand and manufacturing quality of the insulation product
Thermal bridging through framing members and installation defects (Correct answer)
The age and degradation of insulation over a 10-year period
Code-minimum R-values adjusted for climate zone multipliers

Correct answer: Thermal bridging through framing members and installation defects

Effective R-value accounts for the actual whole-assembly thermal performance including heat loss through framing members (thermal bridging) and any insulation installation defects, not just the insulation material alone.

HERS Field Inspection & Testing

When performing a blower door test, at what reference pressure is the airflow typically measured for HERS rating purposes?

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