Last year Bosco and I did a "study" on our tubs. Not a competative thing but I needed a water change and turned down the heater and was reporting about my heat loss. Bosco jumped in with I'll try that too. He had his tub filtering the way it always did and I had my circ pump running.
In the 2 1/2 days that I had turned down the temp, my tub lost about 16 degrees. In the same time Bosco's tub kept it's temp ... we both started at 102 if I remember correctly.
I was impressed that my tub only lost that much temp in 20 and 30 air temps. I was more impressed that Bosco's tub maintained it's temp, he's more north of me so I would think it was at least as cold if not colder.
I have to say based on Bosco's findings that I would consider looking at a Arctic if I ever decide to purchase another tub ... that is assuming that there would be a dealer close by, when I bought my tub there wasn't.
That's my 0.02