Welcome to our forum.
Thanks, smackman. I've updated the Q&A section a bit. There's a thread of at least one owner who reports 3-5 degrees F loss during a 30 minute soak (though the conditions for that user were unclear). Is that acceptable? I don't know. That's subjective. Given the pretty small cost differential between 50a and 60a service, I think most new tub owners would opt for 60, and just not have to worry about temperate issues -- if their homes can support the electrical load.Also, 50a isn't, to my knowledge, "recommended" over the other options by Jacuzzi -- it's just the factory default. In the 2012 pre-delivery guide, page 14, Jacuzzi highlights that is a choice, and gives you 3 options to choose from.
When we soak in the winter time, The temperature is seldom below 32 degrees at night in North Louisiana; I have minimal if any temperature loss.Also the installation of a 50 amp system was much less than a 60 amp.It probably depends on where you live, But below the Mason Dixon line, 50 amp default works with minimal temperature issues. I have owned a 2010 J-465 Jacuzzi for over 2 years. My only significant issue was a bad flow switch and a bad dealer.