So I have been working in the education field since 2012 and I love it , I want to become a special education teacher . The issue is right now where I am in pursuit of my degree , I will need a lot more time in schoo...

It would be temporary use of those fund as I'd cash-out refi the duplex and pull that have into the HELOC.

I would not do a panel upgrade for a temporary solution.

Either way, the result will be a temporary reduction in rent received, or an empty house that they must advertise to get someone else, who usually doesn’t have to move until the following month anyway.

Hopefully I can help a little.So, the way we think about your question is treating your HELOC payment more as a 'holding cost' that counts against your rehab budget, as more than likely, your HELOC balance should be re-payed back down to zero, once you achieve the rehab and cash out refinance / convert the stuff to the long term fixed rate financing.Part of the benefit of thinking of it this way, is that the HELOC payment is temporary while you use that revolving line of credit. 

That would be more cost efficient in my area than installing temporary window units.

Landlord rules are you install it as a permanent structure its mine (insulated and walled the garage) temporary it's yours (huge wall storage, which is too difficult to move he can keep lol)Would I be considered a dirty tenant I don't think so.

They might keep me as temporary part time but I won’t know until weeks from now.

Even if the month to month will be pricey, its only temporary.

"Extensive rehab" sounds like more than a 6 week job, so to list for rent and then go over time could cost you putting tenants up in temporary housing.On top of that, most people cant see beyond what is there, so showing them an unfinished unit could result in either lower rent, or few applicants