Hi JHMURCIA,
Not sure if this would help but have you thought about using solar water heaters to pre-heat water for the hot tub, If you have a 2 bed you could put it on the roof where no one would see, there is a tap there.
I have a 3 bed which is north facing so most of the sun will be in the rear patio area, this gives privacy and there is a tap also, the only prob I see is to get a panel small enough.
It is a project for 2009 spring I think. I will continue to look for a small panel and also to see is it possible to connect to the hot water system inside the apartment.
Hope this will give some food for thought.
Regards, Ken.