Practice Test Geeks(HERS) Home Energy Rater Certification Practice Test
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Ventilation & Indoor Air Quality 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 Ventilation & Indoor Air Quality flashcards as text

  1. An HRV (Heat Recovery Ventilator) differs from an ERV (Energy Recovery Ventilator) in that an HRV:

    Answer: Transfers only sensible heat between airstreams without transferring moisture

    An HRV uses a heat exchanger core that transfers only sensible (temperature) energy, whereas an ERV core also transfers latent energy (moisture) between airstreams.

  2. In which climate condition is an Energy Recovery Ventilator (ERV) generally preferred over a Heat Recovery Ventilator (HRV)?

    Answer: Hot-humid climates (IECC zones 1-3) where moisture control is critical

    In hot-humid climates, an ERV's ability to transfer moisture from the humid incoming air to the drier exhaust air reduces latent cooling loads, making it preferable over an HRV.

  3. A supply-only ventilation system in a hot-humid climate can create which building science concern?

    Answer: Pressurization that drives warm humid air into wall cavities, risking moisture damage

    Supply-only systems positively pressurize the home, which in hot-humid climates can push warm, humid outdoor air into wall assemblies, creating condensation and moisture damage risk.

  4. An exhaust-only ventilation system draws outdoor replacement air into the home primarily through:

    Answer: Intentional envelope leakage paths and passive fresh air inlets

    Exhaust-only systems depressurize the home, causing outdoor air to infiltrate through envelope leakage paths and any intentionally installed passive makeup air inlets.

  5. What is the typical sensible heat recovery efficiency range for a quality residential HRV unit under rated conditions?

    Answer: 70–85%

    Quality residential HRV units typically achieve 70–85% sensible heat recovery efficiency, significantly reducing the energy needed to condition incoming fresh air.

  6. A HERS rater measures a home's exhaust-only ventilation fan at 35 CFM, but the ASHRAE 62.2 design requirement is 45 CFM. This system is:

    Answer: Non-compliant, since measured flow is more than 10% below the design rate

    35 CFM is approximately 78% of the 45 CFM design rate, which is more than 10% below the required rate, making the system non-compliant per ASHRAE 62.2 tolerance limits.

  7. When verifying ventilation compliance during a HERS rating, the rater typically documents ventilation performance by recording:

    Answer: Measured airflow rate in CFM using a flow hood, anemometer, or fan flow meter

    HERS ventilation verification requires measuring actual airflow in CFM at the fan or grille using a calibrated flow measurement device, confirming the installed system meets design requirements.