What is the estimated summer infiltration air quantity for an 1800 sqft residential structure with 8-foot high ceilings in Greensboro, NC?

• A. 30 cfm
• B. 48 cfm
• C. 60 cfm
• D. 75 cfm

Answer: (B)

The calculation of summer infiltration air quantity is important in understanding how much outside air enters a building through unintentional leaks, which can affect indoor air quality and energy efficiency. In residential buildings, the commonly used rule of thumb for estimating the air infiltration rate is based on the size of the structure.

For an 1800 square foot residential structure with 8-foot high ceilings, you can first determine the volume of the space. The volume is calculated by multiplying the area by the height, yielding 14,400 cubic feet (1800 sqft x 8 ft).

In typical conditions, the summer air infiltration rate is often estimated in cubic feet per minute (cfm). For residential structures in similar climates, the average infiltration rate is frequently established around 0.25 to 0.35 air changes per hour (ACH). By applying these figures to the calculated volume and converting that to a per-minute rate, one arrives at a more tailored estimate for that specific structure.

When considering factors such as the local climate in Greensboro, NC, which experiences relatively humid summers, estimating summer infiltration at around 48 cfm serves as a reasonable and practical approximation. This takes into account not only the typical construction methods and materials used in such homes but also