Building pressure diagnostic testing compares which of the following?

Building pressure diagnostic testing is a method used to evaluate how a building interacts with outside air, focusing specifically on the pressure in the entire building compared to the outside atmosphere. This assessment is critical for identifying issues like air leaks, drafts, and overall energy efficiency.

When you assess the pressure of the whole building against the outside air, it provides a comprehensive view of the building's airtightness and helps determine how well the indoor environment is maintained versus external conditions. This is particularly important for ensuring that systems like HVAC function correctly, as imbalances can lead to inefficient heating or cooling, affecting comfort and energy costs.

The other options, while they have contextual relevance in building diagnostics, do not focus on the two-way interaction of the entire building's pressure in relation to the outside environment. Monitoring pressure within individual rooms can give insight into localized airflow issues, pressure differences between ducts may highlight imbalances in the distribution system, and comparing crawl space pressure to living area pressure can be useful for moisture and contaminant assessment but doesn’t provide the broad perspective necessary for understanding building performance as a whole.