A residential balancing report shows three supply terminals at 40, 35 and 25 cfm and two exhaust terminals at 45 cfm each. What is the measured supply-minus-exhaust difference?
- A10 cfm more exhaust than supply.
- 10 cfm more supply than exhaust.
- CNo difference.
- D100 cfm more supply than exhaust.
Where to look it up
Explicit exercise assumptions; not a universal code requirement.
Why B is correct
Supply totals 100 cfm and exhaust totals 90 cfm, so the difference is +10 cfm. This arithmetic does not predict building pressure without considering other air paths.