I presumed because a tenant can easily put a lock on the bedroom door, preventing others from using the egress in an emergency.

The 2012 International Bldg Code (IBC) recently required the air barrier but some places have not adopted this code yet. 

They, most likely, as you stated, wanted to prevent "every yahoo" from knowing their mortgage.  

While you may immediately start eviction within your lease terms, a better solution would be to prevent problems from becoming a property-wide issue.What you need to do:Initiate strong resident screening and vetting protocol.

Hi Steve, I'm not an official expert, but I do dabble with dryer vents both for fun (weird, I know) and in my line of work (plumbing, air, electric).I hope these help:1) 90 degree bends are pretty bad to have because they restrict air flow.

@Brooke Gibson I think I'm pretty qualified to speak on this as I have owned a rental in Buenos Aires and properties in South Africa as well as currently the Midwest.

There is a threshold that prevents you from deducting business expenses?

Many lenders have requirements that you live in the home as your primary residence for 12 months unless there are exigent circumstances (such as a PCS) that prevent you from doing so. 

There is usually supposed to be some play and freedom of movement as with hot and cold weather you will have some flex and expansion occurring.If it's front door then have some off the bottom but need weather stripping to make it air tight and too keep animals out.

Is the heating system forced air or radiators?