In this review, we listed insulated water bottles with a capacity of 18 fl. oz. to 32 fl. oz. As insulated water bottles are relatively heavy, you usually only bring one such bottle with you and keep it within easy reach – for example in the backpack’s side pocket. You will probably need to bring more fluid with you than that, but the rest of the water/beverage you can carry in plastic water bottles stored in your backpack where it gets less affected by high or low temperatures (due to the insulation from clothing, gear etc.). When you empty the insulated water bottle you simply refill it with the water from the plastic bottles in the backpack. Therefore, it rarely makes sense to go for an insulated bottle with a capacity higher than 32 fl. oz. On the other hand, we don’t recommend buying an insulated bottle with a capacity smaller than 18 fl. oz. as it will require refilling too often.
Insulated water bottles feature a special design to reduce the heat transfer by conduction and convection. Any insulated water bottle consists of two bottles where one is placed within the other. The air in the gap between the two bottles is then extracted (creating vacuum) to minimize heat transfer between the two.
It’s a great advantage if the opening of your insulated water bottle allows easy refilling and cleaning by being relatively wide. Furthermore, a wide opening also allows you to insert ice cubs in warm conditions or to store a more chunky soup. The bottle should also be easy to open or close – even while wearing gloves.