Practice Test Geeks(HERS) Certified Home Energy Rating System Rater Practice Test
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Blower Door & Duct Testing Flashcards

7 cards from real HERS practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.

Read the first 7 Blower Door & Duct Testing flashcards as text

  1. What is the primary purpose of performing a blower door test with the HVAC system in its normal operating configuration during a diagnostic test (not a rating test)?

    Answer: To measure duct leakage to outside using the Delta Q method

    Running the HVAC system during a diagnostic blower door test enables the Delta Q method, which estimates duct leakage to outside based on the change in house pressure with the system on versus off.

  2. According to RESNET HERS methodology, which value is used to calculate the HERS duct efficiency penalty?

    Answer: CFM25 total as a percentage of system airflow

    RESNET uses duct leakage expressed as CFM25 as a percentage of the system's design airflow to determine the efficiency penalty applied to the HERS score.

  3. Which of the following is a common source of air leakage that a rater should pre-seal before a blower door test to avoid skewing results toward envelope leakage?

    Answer: Mechanical exhaust fans without dampers

    Mechanical exhaust fans without self-closing dampers are intentional openings that should be temporarily sealed before the test so they don't inflate envelope leakage readings.

  4. When testing a newly constructed home using RESNET protocols, at what project stage should the 'rough-in' duct leakage test occur?

    Answer: Before drywall installation so duct connections are still accessible

    The rough-in duct leakage test is performed before drywall installation so that any failing connections are still accessible for repair by the HVAC contractor.

  5. If a home's total duct leakage (CFM25 total) is 200 cfm and the system airflow is 1,000 cfm, what is the total duct leakage as a percentage of system airflow?

    Answer: 20%

    200 / 1,000 × 100 = 20%, which represents the fraction of system airflow lost through duct leakage.

  6. What safety precaution must be taken with atmospherically vented combustion appliances during a blower door depressurization test?

    Answer: They must be turned off and allowed to cool to prevent backdrafting

    Depressurizing the house can cause backdrafting of combustion gases from atmospherically vented appliances; they must be shut off and cooled before testing.

  7. Which of the following duct sealing materials is NOT typically approved by RESNET/ACCA for sealing duct leakage in HVAC systems?

    Answer: Standard cloth duct tape (gray fabric tape)

    Standard gray cloth duct tape loses adhesion over time and is not rated for HVAC duct sealing; only mastic, UL 181-rated tape, or approved aerosol sealants meet industry standards.