The location of the outside end of the building pressure tubing is very important when setting up your blower door.
When installing the building pressure tubing, be sure the outside end of the tubing is at least 5 feet to the side of the exhaust airflow from the blower door fan. Although it is common practice (and was our recommended installation procedure for years) for blower door operators to insert the open end of the tubing just a few inches through the patch on the nylon panel, and leave it, we have determined that this set up practice can produce inaccurate building pressure readings due to the exhaust airflow from the fan hitting the end of the tubing.
A good location for the end of the building pressure tubing is at the base of the building where it meets the ground. We have redesigned our nylon blower door panels with two access holes near the floor to make it easier to properly install your building pressure tubing. If the fan is exhausting to a porch, garage or other enclosure, it is best to install the end of the building pressure tubing outside of the enclosed space.