Why stainless vacuum insulated water bottle keep cold 24H which longer than keep hot 12H?
My water bottle is a stainless steel, double walled, vacuum insulated vessel. It claims to keep liquids cold for up to 24 hours but only hot for 12 hours. Why are these not the same or at least close to one another?
If your cold stuff has any ice, it will have a hard time melting in there. The hot drinks will lose more energy due to the higher difference in temperature, and the biggest effect is:
If you pour any of the liquid into a cup to drink it, the air entering the vessel does much more to cool off a hot liquid than it does to heat up a cold liquid, due to evaporative effects.
Also, what we mean by “cold” and what we mean by “hot” is different: tea needs like 80 degrees, whereas 10 degrees is still cold: that’s a much larger percentage of the temperature difference that the cold thing has to get past before it’s cold, so it takes longer, even without ice.