I'd put that in but it was not an efficient solution for my vendor for an apartment.  

But im not opposed to adding a 2nd story if that is the more efficient route. 

You shouldn't worry about over paying for labor, just talk to some contractors and finding reasonable prices won't be too difficult In fact, the contractor is probably WAY more efficient at doing the labor than you are so I see it as less cost efficient to do it myself.

A real dehu will cost $00.02 - 00.04, run more efficiently, remove micro-contaminants from the air (hepa filter), and have the strength to shuffle around ALL the air in the basement through the filter. 

You could be a lot more efficient that way, unless you have a good reason to buy cash (like purchasing deals that require all cash).I'd do it though.

Make sure the building is energy efficient with good insulation, thermal windows, and proper weatherizing.

I know it's not the most efficient use of my time, but until I learn something better this is my way of keeping the hustle flowing.Keep 'em coming, anyone else have something to add?  

Read the beginners guide, very informative and efficient.

And remember the US has some of the lowest energy cost on the planet so they folks in Europe and Asia who pay much more for their heating/cooling energy use them because of their energy efficiency.

Tim Gordon 's point, it must be supportable by an efficient end user process that repeatable, scalable and sustainable.