Energy Modeling & Analysis 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 Energy Modeling & Analysis flashcards as text
A rater is modeling a two-story home where the second floor overhangs the first floor by 2 feet. How does this overhang affect the energy model?
Answer: It creates an exposed floor assembly that must be modeled with appropriate R-value and area
A cantilevered floor exposed to outside air must be modeled as a separate exposed floor assembly with its own insulation R-value and square footage.
Which HERS software input directly affects the calculated internal gains used in the energy model?
Answer: Number of bedrooms
RESNET protocols use the number of bedrooms as a proxy for occupant count and appliance loads, which determines internal heat gain inputs.
When modeling a gas fireplace in HERS software, what efficiency value is typically entered?
Answer: The Annual Fuel Utilization Efficiency (AFUE) for the fireplace insert
Gas fireplace inserts with documented AFUE values are modeled using that efficiency; otherwise RESNET default values are applied.
A HERS rater is analyzing a home with both a gas furnace and an electric air conditioner sharing the same duct system. How should this be modeled?
Answer: Enter both systems separately, sharing the same duct leakage inputs
Split HVAC systems are modeled by entering the heating and cooling equipment separately while linking them to the same duct system distribution inputs.
What is the significance of the 'heating degree days' (HDD) value used in HERS energy modeling?
Answer: It quantifies the cumulative heating demand of the local climate over a heating season
HDD reflects how cold and how long winters are at the site, directly influencing the magnitude of annual heating energy calculations in the model.
In HERS modeling software, what is meant by 'distribution system efficiency' for a forced-air system?
Answer: The fraction of heating or cooling energy delivered to conditioned space after duct losses
Distribution efficiency accounts for duct conduction and leakage losses, representing what fraction of the system's output actually reaches the conditioned living space.
A rater is modeling a home with an ERV (Energy Recovery Ventilator). Which efficiency rating of the ERV is most important to enter accurately?
Answer: Sensible and latent recovery efficiency (%)
The ERV's sensible and latent recovery efficiencies determine how much energy is recovered from the exhaust air stream, reducing the ventilation heating and cooling load.