I'm temporarily stuck living in a place where winter is two weeks long...if there is one. So I have the opposite problem-keeping things cold. High temperatures make hyperthermia a very real threat. When perspiration cannot evaporate there is no evaporative cooling and core temperatures rise. The best solution is a space suit with built-in air conditioning. Perhaps Arx'teryx will include one in their 2016 lineup. It can't be much more expensive than some of their products I've bought from Backcountry.
The next best solution is frequently consuming cold liquids, and that's where OR's portable ice box comes it. This bottle parka works even better than the advertising hype would lead you to believe. The first few times I used them I put frozen water bottles in OR parkas only to find everything still frozen hours later. After uttering a liberal string of profanity I had to break out the Gigapower to melt my drinking water!
And I wasn't simply being a smartass earlier when I referred to the bottle parks as an "ice box." Throw in a soap bar sized freezing cube or a small freezer container filled with water then frozen. Then put in breakfast sausage, eggs, about 15g (1/2 oz.) of caviar, a poly-con or small plastic bottle of heavy cream, and a small roll of instant biscuits. In another one add ice as before and a very cold 375 ml bottle of Chapagne or sparkling wine. Wrap them in your sleeping bag. When it's time for vittles, deep fry the biscuits (drain well), cook the sausage, beat the eggs with the heavy cream and cook scrambled eggs with caviar. Serve to your favorite lady (or guy) with the bubbly.
In closing, I "blind purchased" two "Mil-Spec water bottle insulators" from a competitor of Backcountry just to see what they were. When they arrived, I very curiously looked to see who manufactured them. The "OR" tag was quite conspicuous. The Mil Spec parka is shorter but fatter than the commercial model. The insulation is obviously thicker on the Mil Spec, especially the top that covers the cap. Both models accommodate my Nalgene 32oz./1L collection as well as my Eurotrash "High Altitude Water Bottles" which I like much better than the Nalgenes. I'm going to get a few more of the Mil parkas even though they're significantly more expensive. I'll hang the better insulated units on the outside of my pack and pack the commercial units inside out of the sunlight.