Yes, we didn't buy a foundation because we have a waterbed base. If we got rid of that we'd lose all our clothes storage. I mean, its possible, but a pain. The guy that sold us the mattress said the waterbed frame would work. Just as long as it was a flat solid surface.
I think I've also noticed the warmer it is in the house the less hot I get. I know that sounds backwards, but this morning the house was 62 degrees and I was not sweating when I woke up. Last week it was colder (mid 50s) and I was roasting! What the heck??