HERS Thermal Envelope Insulation and Air Sealing Flashcards
6 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 6 HERS Thermal Envelope Insulation and Air Sealing flashcards as text
During a HERS pre-drywall inspection, a rater identifies missing insulation in a rim joist cavity. Why is this location particularly important?
Answer: Rim joists are a significant thermal bridge and air leakage point at the foundation-to-wall junction
Rim joists are a major source of both heat loss and air infiltration at the critical junction between the foundation and above-grade framing.
What does the term 'thermal bypass' refer to in a HERS field inspection context?
Answer: Air movement around or through insulation that reduces its effective R-value
A thermal bypass is any air movement pathway that allows air to flow around insulation, significantly reducing its effective thermal resistance.
Which insulation material has the highest R-value per inch, making it useful where space is limited in a HERS-rated home?
Answer: Closed-cell spray polyurethane foam
Closed-cell spray polyurethane foam achieves approximately R-6 to R-7 per inch, the highest of common residential insulation materials.
A HERS rater is evaluating a home with a vented crawl space. Under current best practice, what is the preferred energy-efficient crawl space configuration?
Answer: Sealed and conditioned with insulation on the crawl space walls
A sealed and conditioned crawl space with insulation on the perimeter walls is the preferred configuration for energy efficiency and moisture control.
During HERS verification, a rater checks that window U-factors meet IECC requirements. What does a lower U-factor indicate?
Answer: Higher thermal resistance (better insulation)
U-factor is the rate of heat transfer; a lower value means less heat flows through the window, indicating better insulating performance.
What is the primary purpose of a vapor retarder in a wall assembly from a HERS building science perspective?
Answer: To control moisture diffusion and prevent condensation within the assembly
A vapor retarder controls the diffusion of water vapor through the wall assembly to prevent condensation and moisture damage within the building envelope.