There’s nothing like a nice, cold drink of water on a hot summer day. You’ve packed up your trusty Nalgene Bottle, filled it with ice cold water, and hit the surf for a few hours… only to find that your bottle is sweaty and your water is lukewarm.
Gross.
So why is it that Nalgene Bottles don’t keep water cold for long? And how long can a Nalgene actually maintain your water’s temperature?
Nalgene Bottles don’t keep water cold for long because they’re not insulated. A Nalgene full of cold water will stay cold for an hour or two depending on the temperature outside. A Nalgene Bottle full of ice water can last for about 3-4 hours in the same conditions.
Using an insulating sleeve or pre-freezing water in your bottle can help quite a bit, but ultimately Nalgene Bottles aren’t designed to maintain the temperature of your water and you're better off opting for a vacuum-insulated bottle like a Hydro Flask or a Yeti.
If having ice cold water all day is important to you, a Nalgene is the wrong bottle. But if you just need a simple, inexpensive, durable bottle, a Nalgene is likely a great fit.
Why Don’t Nalgene Bottles Keep Water Cold?
Nalgene Bottles don’t keep water cold for long because of the simple fact that they’re not insulated. Nalgene bottles are made from a single layer of Tritan Renew plastic, which is a BPA and BPS free plastic.
Even stainless steel Nalgenes are only made from a single layer of stainless steel. They are one of the few non-insulated stainless steel bottles you’ll find.
In order for a bottle to be insulated it needs to have a layer of some sort of insulation that prevents heat transfer. Like in the case of a cooler this could be a foam layer but water bottles generally use a vacuum layer as their primary insulation.
Vacuum is the best insulation as there is no medium for the heat to pass through. Insulated water bottles can keep drinks ice cold for up to 3 days! A Hydro Flask is much better than a Nalgene at keeping drinks cold because they have this vacuum insulation whereas Nalgene doesn't.
But it’s not all bad.
Non-insulated bottles have a couple of advantages.
They’re lighter weight, can be used as hot water bottles, and have no vacuum-insulation to lose when dropped or machine washed. So they are less likely to “break”.
Some vacuum insulated bottles aren't dishwasher safe but all Nalgene bottles are dishwasher safe making them very easy to clean. You can also cook food or sterilize water over a fire in the stainless steel Nalgene bottles due to the fact they aren't insualted.
If keeping water hot or cold for an extended period of time is a priority for you then a Nalgene (or any plastic bottle for that matter) probably isn’t the best choice for you.
For the best ice or heat retention possible look to Klean Kanteens over Nalgenes, they’re able to keep water cold for days (literally), and probably suit your needs better. They are also one of the best eco-friendly water bottles on the market.
How Long Do Nalgenes Keep Water Cold?
The amount of time a Nalgene Bottle will keep water cold depends on many factors.
The biggest things to consider though are the temperature outside, the amount and type of ice in the bottle, and exposure to sunlight.
The estimates below are for 32 oz plastic Nalgene Bottles kept out of direct sunlight. Just keep in mind, they’re only rough estimates. Your mileage may vary.
| 60°F | 75°F | 90°F | |
| Cold Water With No Ice | 1-2 hours | 1 hour | <1 hour |
| Water With Ice Cubes | 3-4 hours | 2-3 hours | 2 hours |
| Half Frozen Bottle | 6-8 hours | 6 hours | 4-5 hours |
| Full Frozen Bottle | 12+ hours | 8-10 hours | 6-8 hours |
Feeezing a half-full Nalgene on its side the night before is my favorite Nalgene hack to make water stay cold longer.
It creates a large chunk of ice that melts much slower than individual cubes would and keeps your water cold for a good portion of the day in normal conditions.
An insulating sleeve can also help, and will add at least a couple of hours to any of the estimates above.
Neoprene sleeves, like this one by Nalgene, are my favorite because they insulate well and do a great job of absorbing sweat as your bottle warms.
This handy neoprene sleeve fits perfectly onto any 32 oz Nalgene bottle and helps to keep your drinks colder longer and will reduce sweating. Features a draw string for a tight fit and a side clip for easy carrying.
