I'd avoid doing this in units with shared ventilation as there is a potential risk of irritation to someone's lungs with prolonged exposure, especially if the person already has existing lung disease.Ozone machine will run about 60 bucks on Amazon.

Some people seemed irritated by how much customization they had do to the CRM to fit into real estate use cases.If there was the perfect real estate CRM, how do you think it would look like?

You don't know at this point exactly what's going on, whether you just have an irritable tenant, or if the Lease is being violated.

Having roommates can be irritating, but as you said duplexes are more difficult to find in most markets. 

And irritate the construction unions?!

I'd be irritated too if someone kept coming back to my house daily to tinker with the ac. 

We don't know what states the properties reside.Florida, Georgia, Hawaii, Illinois, Indiana, Montana, South Dakota, Virginia have different laws.Oh, and by the way, an attestation to the insurer and others (mortgagee) will not change premiums nor constitute a “sale.”There are considerations such as the loss of asset protection after judgment (beneficial interest is personal property, not real property), but if the property is clear of a mortgage and the concern is title theft (a concern you raised), then putting the property into a land trust is probably a lower cost alternative to maintaining a debt (which irritates the wife). 

The more you want to deal with this the more irritating you will have.

Interest rates could be 50% right now, but if we are getting a 20% IRR it doesnt matter.Real estate prices have increased considerably in recent years due to low interest rates.

The husband states "we will pay 1600 but these other two will have to come up with the rest cause I ain't paying the rest" and appeared to be irritated .