HERS Building Science Principles 2

Question 1

Which phenomenon causes warm, moist air to condense on a cold surface inside a wall assembly?

Accepted Answer

Dew point condensation

Answer

Thermal bridging

Answer

Stack effect pressure

Answer

Vapor diffusion equilibrium

Question 2

In a hot-humid climate, where should the vapor retarder be placed in a wall assembly?

Accepted Answer

On the exterior side, toward the hot exterior

Answer

On the interior (warm-in-winter) side

Answer

In the center of the cavity

Answer

No vapor retarder is needed in hot-humid climates

Question 3

What does the term 'thermal mass' refer to in building science?

Accepted Answer

A material's ability to store and slowly release heat

Answer

The total weight of insulation in a wall

Answer

The R-value of a dense-pack insulation product

Answer

The ratio of conduction to convection in a building envelope

Question 4

Which heat transfer mechanism does low-emissivity (low-e) window coating primarily reduce?

Accepted Answer

Radiation across the air gap

Answer

Conduction through the glass

Answer

Convection at the glass surface

Answer

Air infiltration around the frame

Question 5

A HERS rater measures attic ventilation to ensure balance between intake and exhaust. What is the recommended ratio of net free area to attic floor area when using balanced ventilation?

Accepted Answer

1:150

Answer

1:100

Answer

1:300

Answer

1:600

Question 6

What is the primary purpose of an air barrier in a building enclosure?

Accepted Answer

To resist convective air movement through the building shell

Answer

To prevent vapor diffusion through materials

Answer

To add R-value to wall assemblies

Answer

To control solar heat gain through windows

Question 7

Which condition best describes a 'negative pressure' house?

Accepted Answer

Interior air pressure is lower than exterior pressure

Answer

Interior air pressure is higher than exterior pressure

Answer

Pressure is equal on all sides of the envelope

Answer

The HVAC system is over-sized for the heating load