Amithlon :
minimum temp i've seen is 7 C - actually below room temp ! (18 C)
That's because you're getting a false reading. Think about it. Apply physics, or at least 7th grade earth science. It can't possibly be below room temperature unless you're using some kind of chiller (a TEC, refrigeration mechanism, etc).
We review a lot of coolers and see lots of reports from reader about our "bogus" numbers. But the people who make these bold statements often don't understand the basic science that says that their own numbers are counter-factual.