Which factor is crucial when considering filter selection to maintain IAQ without creating excessive pressure drop in a high-RH building?

Prepare for the HVAC 403A Exam. Study with flashcards and multiple choice questions, each question has hints and explanations. Get ready for your exam!

Multiple Choice

Which factor is crucial when considering filter selection to maintain IAQ without creating excessive pressure drop in a high-RH building?

The factor being tested is the trade-off between filtration performance and the resistance a filter creates in the system. A higher MERV filter captures more contaminants, which improves IAQ. But as filtration efficiency increases, so does the pressure drop across the filter. If the system isn’t adjusted—by increasing fan power, selecting a filter with a lower pressure drop, or compensating with staged filtration—the airflow can drop. In a high-RH building, maintaining adequate airflow is crucial for proper humidity control and overall IAQ, so recognizing the need to compensate for the added resistance is key. This is why the statement that higher MERV provides better filtration but increases resistance and may reduce airflow if not compensated is the best choice.

The factor being tested is the trade-off between filtration performance and the resistance a filter creates in the system. A higher MERV filter captures more contaminants, which improves IAQ. But as filtration efficiency increases, so does the pressure drop across the filter. If the system isn’t adjusted—by increasing fan power, selecting a filter with a lower pressure drop, or compensating with staged filtration—the airflow can drop. In a high-RH building, maintaining adequate airflow is crucial for proper humidity control and overall IAQ, so recognizing the need to compensate for the added resistance is key.

This is why the statement that higher MERV provides better filtration but increases resistance and may reduce airflow if not compensated is the best choice.

More practice questions