Most children are being insulated from these things, I bet they would love to be involved with it in some capacity.

Exterior walls on inside (signs of some water damage, repair brick / insulation / sheet rock appropriately).

You need to insulate yourself from demotivators.

You may then need to add a little insulation and move some electrical and duct work in the new ceiling space.

I personally believe it has to do with laudy insulation nnn 

With a building that's 80 years old, you would hope that there were updates to plumbing, electrical, insulation.

Here are some ways to increase cash flow from your properties:1.Raise rent: Regularly reviewing and increasing rent can help increase cash flow from your properties, but it’s important to ensure that the rent remains competitive and in line with the local market.2.Improve property management: Hiring a professional property management company can help streamline operations and increase efficiency, freeing up more cash flow.3.Increase occupancy rates: Increasing occupancy rates through effective marketing and tenant retention strategies can increase cash flow by reducing the amount of time the property is vacant.4.Implement energy-efficient upgrades: Making energy-efficient upgrades, such as installing energy-saving appliances or adding insulation, can help reduce utility costs and increase cash flow.5.Implement a preventative maintenance program: Regularly maintaining and repairing properties can help reduce the costs of major repairs down the road and increase cash flow.6.Diversify your portfolio: Diversifying your portfolio by investing in multiple properties in different geographic locations and markets can help reduce risk and increase cash flow.7.Refinance: Refinancing your properties can help lower your monthly mortgage payments, freeing up cash flow for other expenses or investments.By implementing these strategies, you can increase the cash flow from your properties and achieve a higher return on your investment.

Maybe the house is very well insulated and you ave no fresh air mixer on your HVAC system.Maybe the fresh air mixer (option) is there and it's turned to zero (off).Maybe adding a fresh air mixer and alerting the renters about it would solve some of this problem.Good Luck!

Also, there was no insulation or vapor barrier under the house - electric bill was $800 for December/January.

She was complaining about it being cold, and here they are ready to do a FULL day of work so that by this evening she had a new insulated wall with new pipes and new window....and she sent them away.