Building Science Fundamentals 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 Building Science Fundamentals flashcards as text
What is the primary function of a drain-plane (drainage plane) in a wall assembly?
Answer: To provide a path for water that penetrates the cladding to drain out
A drainage plane directs any water that gets past the cladding downward and out of the wall assembly before it can cause damage.
In building science, what does 'hygrothermal analysis' evaluate?
Answer: The combined heat and moisture movement through building assemblies over time
Hygrothermal analysis models both heat (hygro = moisture, thermal = heat) transport simultaneously to predict condensation risk and durability in assemblies.
A homeowner complains of condensation on interior window surfaces in winter. Which condition is the most likely cause?
Answer: The window U-factor is too high relative to indoor relative humidity and temperature
Windows with high U-factors (poor thermal performance) have colder interior surface temperatures that fall below the dew point when indoor humidity is elevated.
Which climate zone classification system is used by the IECC and referenced in HERS ratings?
Answer: IECC/DOE climate zones 1–8 based on HDD and CDD thresholds
The IECC uses DOE climate zones 1–8, which are defined by heating and cooling degree-day thresholds, and are the basis for building energy code requirements.
What is 'interstitial condensation' and why is it a concern in building assemblies?
Answer: Condensation occurring within a wall or roof assembly where water vapor meets a surface below its dew point
Interstitial condensation forms inside a building assembly and can cause structural decay, mold, and reduced insulation performance without visible exterior signs.
Which type of heat transfer is dominant in a radiant barrier system installed in an attic?
Answer: Radiation between the hot roof deck and the attic floor
Radiant barriers work by reflecting long-wave infrared radiation emitted from the hot roof deck, reducing radiant heat gain to the attic floor and insulation.
In the context of building envelope performance, what is 'air washing' of insulation?
Answer: Cold air moving through or around insulation, degrading its effective thermal resistance
Air washing occurs when cold air infiltrates around or through insulation, carrying heat away by convection and significantly reducing its effective R-value.