The doors are damaged and need replaced anyway.  

The original goal was to rehab, appraise, and replace the private lender with a conventional loan.If I were to sell, I could initially offer 100% O.F. for about 6 months, then I would need to get enough cash (call that amount 150K) out to pay back my private lender. 

I am leaning towards replacing the door now. 

I'm going to replace that tonight to confirm that's where the leak is from. 

@Kenneth Garrett according to the PA code, if there is a window within 10 feet of a fire escape, that is changed i.e. removing the frame then it needs to be replaced with a fire rated window assembly.

If the property is constantly losing money and it's not a one-off sort of problem (i.e. big turnover or roof replacement, etc.) and you can pull out some money selling, I would recommend selling.

. @ 4% (30% of rent)Even if you want to cash flow just $150 a door, that would be 20% of rent, leaving 40% of rent for everything else (100%-10%-30%-20%=40%)40% of $800 or $320, is then what needs to be left at a minimum for monthly 1) property tax, 2) insurance, 3) vacancy, 4) maintenance, 5) capex, 6) tenant replacement, 7) tenant renewal and 8) lawn maintenance costs. $320 for all these categories just doesn't seem feasible on a monthly basis.Therefore, I think it's safe to say that it's either your cash flow that declines (e.g., <$100/mo.) or you hope there's months with little to no 3) vacancy, 4) maintenance, 5) capex, 6) tenant replacement, and 7) tenant renewal costs, which would be foolish.

. @ 4% (30% of rent)Even if you want to cash flow just $150 a door, that would be 20% of rent, leaving 40% of rent for everything else (100%-10%-30%-20%=40%)40% of $800 or $320, is then what needs to be left at a minimum for monthly 1) property tax, 2) insurance, 3) vacancy, 4) maintenance, 5) capex, 6) tenant replacement, 7) tenant renewal and 8) lawn maintenance costs. $320 for all these categories just doesn't seem feasible on a monthly basis.Therefore, I think it's safe to say that it's either your cash flow that declines (e.g., <$100/mo.) or you hope there's months with little to no 3) vacancy, 4) maintenance, 5) capex, 6) tenant replacement, and 7) tenant renewal costs, which would be foolish.

I would think it is a pretty common size, as the big box stores sell replacement windows in those sizes.

If people living in them have took care of them and/or items have been replaced and routine maintenance done, it may be worth it to keep them.