The installer did not remove the original weights from the original 100 year old windows nor did he insulate the weight shafts which is a must in Northern New Hampshire where temperatures often drop to -20.

There is nothing that exists that will completely insulate your rental property from complete liability, because the minute it is rented, you are exposing yourself to liability.

Now, if sitting on a pile of cash, that is "insulation" or PROTECTION for the various "what-if's" that can and WILL arise for persons in such OVER-leveraged positions.

I.e New roof Central ac for two unitsNew kitchen and bath both units New electrical (old outdated)Front and rear porches need to be redoneNew plumbing (frozen pipes) house wasn’t winterized New drywall Can reuse most of the windows just new screens Security system and cameras New lightning (flush lighting) New roof on the garage and garage doors (possibly insulate) for winter time want to add a 1/2 bath to the first floors of each unit (More rental appeal 3bd 1bth vs 3bd 1.5 bath) Siding And paint Had ideas since it’ll be home of doing spray insulting to the attic  (livable space)  (save on heating and cooling cost long term)  So as you are networking get referrals for as many contractors as you can.

In the event that one tenant goes crazy and tries to sue me, I want to have a legal separation between the entities so they are insulated from legal recourse on all of them.

The attached images show the attic's current condition.The room in the back is insulated and and would require finished flooring, heat, & paint (62 sqft above 7 ft height). 

If there is mold, it will usually be A) on the subfloor exterior, joists, and insulation in the crawlspace, or B) in any areas of water damage/water leaks inside the walls, behind tile in bathrooms, etc.

That being said there is certain kinds of insulation you can use that is specifically designed to reduce sound. 

This is the biggest house I’ve flipped so far.the other two were about 1800 ft.² single-story homes.As far as ADU goes, I have already passed framing, electrical, plumbing, insulation, sheer wall, and HVAC and installed all windows & door.

Economic resilience: The Midwest's diverse economic base, including agriculture, manufacturing, and emerging tech sectors, provides some insulation from market volatility.As an active investor in Wisconsin and Minnesota I have seen a lot of great growth from appreciation and rent.