People get all caught up on blower door tests now days, and I guess I can see why; they let you know how much air is 'leaking' from the structure.
Ok, that's fine, but in the end, does the amount really matter? I mean, do you really care if the building is leaking 400 cfm or 200 cfm; a leak is a leak, and it needs to be fixed.
Here's a little trick; pressurize the building using the HVAC system's outside air damper.
(Careful, you can damage the building if you pressurize it too much! If you're not sure how much is too much, DON'T DO THIS!! I mean it, you can blow windows out and turn a rubber roof into a really big ballon animal....bad stuff)
Once the building is slightly pressurized talk a stroll around the exterior with an infrared camera; the leaks will be obvious.
You may not know what the leak rate is, but you know something the blower door guys don't; you know where the leaks are!
Want to learn the proper way to perform this test? Drop me a comment.