The return cavity may be sucking in air elsewhere i.e. walls with a bad seal or the attic, therefore bypassing the filter. 

Real estate meetups and investor groupshanding out lots of business cards/telling people what you dohelping others brings karma in your directionstopping at a rehab in progress and asking questionsdriving for $$vacant housesdirect marketingfacebook pageswebsiteIt is doing some or all of the above that will get you 2 or 3 or maybe even 10 deals a month, depending how hard you do them. 

I found this:§ 5307.01Tenants in common, survivorship tenants, and coparceners, of any estate in lands, tenements, or hereditaments within the state, may be compelled to make or suffer partition thereof as provided in sections 5307.01 to 5307.25 of the Revised Code.The content of the petition is governed by statute:§ 5307.03.A person entitled to partition of an estate may file his petition therefor in the court of common pleas, setting forth the nature of his title, a pertinent description of the lands, tenements, or hereditaments of which partition is demanded, and naming each tenant in common, coparcener, or other person interested therein, as defendant.The Court orders partition:§ 5307.04.If the court of common pleas finds that the plaintiff in an action for partition has a legal right to any part of the estate, it shall order partition of the estate in favor of the plaintiff or all interested parties, appoint one suitable disinterested person to be the commissioner to make the partition, and issue a writ of partition.

However, if you can't remember where the money came from, or there was an oral agreement that the funds represented a gift to your husband followed by his contribution to his IRA, life is good.

Is the average rent you quoted based on 2BRs, 3BRs, 1BR, SFR, condos, high rises, or all lumped and averaged?

Technically under the FCRA you could just tell them orally.

For those that plan to organize their loans in this manner where some or all of them may be called on demand that DO NOT have the cash to pay off the loans the decision about what to do is more of a business decision than a legal one in my opinion.  

Like mentioned earlier, you really only need 12" of cavity space to run some flex duct.

Even in a 1031 exchange it is the adjusted basis that carries over so even though you don't have to pay it, if you have taken some or all of the depreciation, it will follow you into the new property.  

Or all of the above to get several streams going.