Building Envelope and Insulation Flashcards
6 cards from real CEM practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 Building Envelope and Insulation flashcards as text
What does the R-value of insulation measure?
Answer: Thermal resistance to heat flow in hr·ft²·°F/BTU
R-value measures the resistance of insulation to heat flow; higher R-values indicate better insulating performance.
The U-factor of a window assembly represents:
Answer: Overall heat transfer coefficient in BTU/(hr·ft²·°F)
U-factor is the rate of heat transfer through a window assembly per unit area per degree of temperature difference, with lower values indicating better insulation.
Solar Heat Gain Coefficient (SHGC) of a window measures:
Answer: The fraction of incident solar radiation admitted through the window
SHGC ranges from 0 to 1 and represents the fraction of solar energy that passes through the window as heat gain into the building.
Air infiltration through a building envelope wastes energy primarily because:
Answer: Unconditioned outdoor air must be heated or cooled to maintain indoor comfort
Infiltrating outdoor air at different temperatures from indoor setpoints requires the HVAC system to expend energy conditioning that air, increasing heating and cooling costs.
A blower door test is used to:
Answer: Quantify building envelope air leakage at a standardized pressure
A blower door depressurizes the building to 50 Pa and measures airflow required to maintain that pressure, quantifying total envelope leakage.
Thermal bridging through wall studs reduces effective wall R-value because:
Answer: Wood or metal studs conduct heat more readily than insulation, bypassing its resistance
Metal and wood studs conduct heat far better than insulation, creating pathways that bypass insulation and lower the whole-wall effective R-value below the nominal cavity R-value.