I’ve been looking into ventilation systems/building pressures and there are a couple of areas I have struggled to find information on for residential applications.

In a home with a positive pressure balance to its ventilation system, what is considered the desired amount of positive pressure? (In commercial buildings, it appears that 0.05iwc positive pressure is common)

Where is the outside pressure tested from in a home? I could see pros & cons of a reference to outside pressure being made in an unconditioned attic, but I can’t think of a better place that isn’t subjected to wind loads.

Any clarity you can provide would be much appreciated.