Total of 11 single pane windows and wanting to get energy efficient replacements .

The more homes you own, their theory is, that at some point those vacancies will be a strain on your cash flow and you might start missing payments on their loan to you.

this is what scares me ( I think this may not be the best route....if it is vacant a few months it could put a strain on me...especially with taxes and insurance).  

I have single pane windows that are probably "bad" in a few of my rentals, I change them out as needed. 

Windows should be double pane, not the old, aluminum stuff.

Calvin Strain PP = ARV - 10% ARV - Repair - ProfitSteven D Nicholson No, repairs have no percent on anything.

He said, "I launched a rock into the sliding glass door with a weed eater and it shattered the outer pane".

My strain of thought is - when the big players buy lands in the millions and the construction go in the tens of millions I'm sure someone lend them money for both land and construction, is there any solution for a he little guy ?

Being a 1950s house, the windows/doors were wooden, poorly insulated and single-paned.

It does have old single pane windows that I have thought about upgrading depending on the appraisal, which I think will help justify the increase in rent easily with savings in energy cost.