So you want an insulated water bottle, but where to begin? In the last few years, the market has seen an absolute explosion in insulated water bottles, both from familiar manufacturers and new brands previously unheard of.
One of the demands water bottle manufacturers have best been able to satisfy is the need for insulation. Insulated bottles keep their contents hot or cold by limiting heat transfer between the bottle’s contents and the atmosphere outside. With a bit of clever engineering behind it, well-made insulated bottles are capable of keeping ice frozen even in the most blazing heat for hours on end or keeping your soup or hot coco warm inside even if immersed in snow.
We put together this article to help you find the best insulated bottle your money can buy. Below, we’ll explain our methods, take a look at some data, and provide some reviews of our top insulated water bottle picks.
The article was originally published on February 13th, 2016.
Finding the Best Insulated Bottle For Your Needs
First let’s explore a little bit about how the type of insulation, how the best insulated bottles work their magic, and then take a look at some specific brands and models to weigh in a little bit on the best purchasing decisions.
Before we get into details, let’s introduce our top five best insulated water bottles which we’ll be using in our comparisons below. You can get some quick details from them on this chart, or hit the links to navigate to more information on each bottle.
Top 5 Insulated Water Bottles Comparison
Types of Insulated Water Bottles
In the world of water bottles, the word “insulated” tends to get thrown around quite a lot, enough to confuse people about just what it means. The word “insulation” technically refers to any material which helps prevent heat loss or transfer, so by this very liberal definition, every water bottle has some form of insulation. But that is not really what you are looking for if you want the kind of insulation that will keep your smoothie frosty on a hot day.
The confusion doesn’t end here: you might also come across references to things like “insulating sleeves” or similar terms. These do provide some degree of limited insulation, but again, are hardly the type of full-blown insulated bottle which will be the primary focus of this article.
The best type of insulation when it comes to water bottles is inarguably Double-Walled Vacuum Insulation. This is the technology behind the original Thermos, and has recently been put to great use by modern companies such as Hydro Flask and Klean Kanteen to produce a wealth of well-insulated water bottles. Actually quite an old technology, double-walled vacuum insulation was invented in 1892 by James Dewar and has been in use for over a hundred years, commonly referred to as a “vacuum flask” or “Dewar flask.” Under this name, the technology has found itself employed in a huge range of applications in science in industry.
Double-Walled Vacuum Insulation 101
As long and fancy as the name might sound, the concept behind vacuum insulation is remarkably simple. The “double-walled” part of the title gives away the whole design. Vacuum flasks achieve their insulation by using two walls with a tiny gap of evacuated air (or vacuum) between them. This means that, in a double-walled vacuum insulated water bottle, you get a kind of “bottle in a bottle” effect, where the container which your liquids contact is itself enclosed.
Why does this keep things hot or cold? The important thing to consider is heat transfer. Inside a vacuum flask, the contents of the bottle have almost nowhere to transfer heat to. Since there is a gap of vacuum between the two walls in the bottle, there is hardly any air or other material to absorb and transfer the heat inside the bottle. This means that the contents – be they hot or cold – stay more or less the temperature at which they were put inside the bottle.
Check out this super helpful diagram from Thermos explaining how double-walled vacuum insulation works.
Best Double-Wall Vacuum Insulated Water Bottle Brands
Now that we have some idea of how it works, our next question is which specific brands of bottle accomplish this the best? All of the bottles employing this technology on the market are made from stainless steel, which certainly takes the materials question off the table. It is important to remember that as this is something of a standardized design, there are often more similarities than differences between these products.
If insulation capability alone is your only deciding factor, you might find choosing quite difficult. This is because among these types of insulated water bottles, insulation is often virtually identical from bottle to bottle. We proved this to ourselves during our evaluation of bottles for this list (more on that below.)
How We Chose the Best Insulated Water Bottles
Over the years we have owned and tested dozens of insulated water bottles. When we set out to perform these tests, we narrowed the options down to about two dozen bottles. We assessed them for their overall quality, their insulation, durability, functionality, appearance, and affordability. We identified the most popular brands in each category. After testing, we narrowed it down to ten bottles.
The top five bottles were put to the test with the methods you see below. We collected comprehensive insulation testing data from our top five bottles. The five runner-ups were not included in the insulation test, but we have given them all a mention below.
Here’s the complete list of our top ten insulated water bottles.
Top 5 Insulated Bottles
- 1. Hydro Flask — More Info
- 2. YETI Rambler — More Info
- 3. S’well Bottle — More Info
- 4. Klean Kanteen — More Info
- 5. Takeya Thermoflask — More Info
Runner-Up Best Insulated Bottles
- 6. FNova Flask — More Info
- 7. Fifty/Fifty Insulated Water Bottle — More Info
- 8. Thermos Beverage Bottle — More Info
- 9. refresh2go Excursion Insulated Bottle with Straw & Filter — More Info
- 10. Cayman Fitness Bottle — More Info
Our Water Bottle Insulation Testing Methods
We subjected our top 5 bottles to two different tests and repeated them for hot and cold liquids. Our methods were quite simple:
- Open-and-Close Counter Test: In this test we filled our bottles with hot/cold water and let them stand on the counter. Every 2 hours, we opened the bottles to test their temperature, then sealed them. We conducted this test for 10 hours.
- Sealed Counter Test: In this test we filled our bottles with hot/cold water and let them stand on the counter for 24 hours without opening them. We then measured the temperature the next day. We repeated this test, starting over fresh, with a 48-hour duration during which the bottles were not opened.
Let’s see what we found out.
10-Hour Open-and-Close Best Insulated Bottles Challenge
Since this test involves opening the bottles every 2 hours, the temperature of the bottle changes much more rapidly than in our Sealed Test. This proved especially true in our heat test, probably because heat rises rapidly through the lid each time it is opened.
In our Cold Insulation Test we found a remarkable similarity between all five of our bottles. We filled each bottle with 40° Fahrenheit with chunks of ice and let them stand on our kitchen counter in the tropics. Every 2 hours, we opened the bottles and tested them with a digital thermometer.
After taking averages for the increases over 10 hours, we found the Hydro Flask had come out ahead.
Increase In Temperature After 10 Hours of COLD Open-and-Close Insulation Test
- Hydro Flask Average: 1.2° increase/hr – Final Temperature: 52°
- Takeya Thermoflask Average: 1.3° increase/hr – Final Temperature: 53°
- YETI Rambler Average: 1.4° increase/hr – Final Temperature: 53°
- Klean Kanteen Average: 1.5° increase/hr – Final Temperature: 55°
- S’well Bottle Average: 1.5° increase/hr – Final Temperature: 55°
Decrease In Temperature After 10 Hours of HOT Open-and-Close Insulation Test
For this test, we filled each bottle with 150° Fahrenheit water. They were left to stand on our kitchen counter in the tropics. Every 2 hours, we opened the bottles and tested their temperature with a digital thermometer.
In general, insulated bottles perform better with cold than heat. This is reflected in their advertising, where the advertised insulating time for hot liquids is usually half the time advertise for cold.
We’re not entirely sure why, but our results varied much more for the heat insulation test than for the cold. In particular, the YETI Rambler really stood out ahead of the pack for its heat insulation in a way that no bottle managed to distinguish itself in the cold insulation test.
- YETI Rambler Average: 3.1° decrease/hr – Final Temperature: 119°
- Hydro Flask Average: 5.1° decrease/hr – Final Temperature: 99°
- Takeya Thermoflask Average: 5.25° decrease/hr – Final Temperature: 97°
- Klean Kanteen Average: 5.4° decrease/hr – Final Temperature: 96°
- S’well Bottle Average: 5.8° decrease/hr – Final Temperature: 92°
12-, 24-, and 48-Hour Sealed Best Insulated Bottles Challenge
In these tests we filled each bottle with hot or cold water and left them to stand on our counter. Each bottle was sealed immediately after being filled and was not opened for the duration of the test. We left the bottles for the full time of their advertised insulation. In the case of all 5, this was 24 hours cold/12 hours hot.
Because we didn’t open the bottles at all, they retained heat much better than with our Open-and-Close test. Every time you open the bottle and expose it to the atmosphere a lot of heat is transferred. The best way to maximize insulation is to keep the bottle sealed. When sealed, we find that these bottles do a good job of living up to their advertised insulating abilities.
Increase In Temperature After 24- and 48-Hour COLD Sealed Insulation Test
In this test, we filled the bottles with 40° Fahrenheit water with chunks of ice and let them stand on our counter. We left them first for the full 24 hours which is advertised as their full insulating time for cold liquids. The bottles were not opened or disturbed during this 24 hours. Immediately after opening them we measured the temperature with a digital thermometer. After the test, the bottles were dumped out and we repeated the test for 48 hours.
- YETI Rambler Final Temperature (24 Hours): 46° (+6°) — 48 Hours: 63° (+23°)
- Hydro Flask Final Temperature (24 Hours): 46° (+6°) — 48 Hours: 64° (+24°)
- Takeya Thermoflask Final Temperature (24 Hours): 47° (+7°) — 48 Hours: 65° (+25°)
- Klean Kanteen Final Temperature (24 Hours): 47° (+7°) — 48 Hours: 66° (+26°)
- S’well Bottle Final Temperature (24 Hours): 48° (+8°) — 48 Hours: 66° (+26°)
Decrease In Temperature After 12- and 24-Hour HOT Sealed Insulation Test
For this test, each bottle was filled with 150° Fahrenheit water and left to stand on our counter. We tested the bottles first for their maximum advertised time for heat insulation (12 hours,) then repeated the test for double that time (24 hours.) During the test, the bottles were not opened nor disturbed. After 12 hours, we opened the bottles and immediately measured the temperature with a digital thermometer. We then refilled them with 150° water and repeated the test with a 24 hour duration.
- YETI Rambler Final Temperature (12 Hours): 120° (-30°) — 24 Hours: 74° (-76°)
- Hydro Flask Final Temperature (12 Hours): 98° (-52°) — 24 Hours: 71° (-79°)
- Takeya Thermoflask Final Temperature (12 Hours): 96° (-54°) — 24 Hours: 72° (+78°)
- Klean Kanteen Final Temperature (12 Hours): 95° (-55°) — 24 Hours: 70° (-80°)
- S’well Bottle Final Temperature (12 Hours): 89° (-61°) — 24 Hours: 70° (-80°)
Our Top Picks
Below we’ll take a closer look at the insulated bottles we used in our insulation test. In addition to the top five insulated bottles we tested, we felt we had to include a few other insulated options as well. While we couldn’t include them in our test above, we felt it would be disingenuous to call this article the “Best Insulated Bottles” without mentioning these contenders as well. So in addition to the top five compared above, we’ve include five runner-up bottles that also have their own special place in the insulated bottle family.
1. Best Insulated Bottle: 40 Ounce Hydro Flask (~$30 on Amazon.com)
The Hydro Flask still remains, day in and day out, my go-to selection for an insulated stainless steel water bottle. It has some of the best insulation I have ever come across, and in my practical experience it always seemed to be the best insulated bottle I’d ever used. This was confirmed by our insulation testing, and we finally got some hard numbers to confirm that Hydro Flask is the Best Insulated Water Bottle.
Though the YETI Rambler pulled ahead in the heat insulation test, Hydro Flask outperformed it in the cold insulation. It also offers a much wider selection and a better value-to-cost ratio than the YETI Rambler.
The Hydro Flask has a stylish look, is available in a huge range of colors and sizes, and is accompanied by a wealth of accessories which allow the bottle to be customized in all sorts of different ways. They are virtually indestructible through normal use and brilliantly well designed and constructed.
In mid-2016 Hydro Flask introduced the latest generation of their wide mouth bottles, featuring a new innovation known as the Flex Cap. Incorporating their new Honey Comb Insulation Technology into the lid, the Flex Cap Hydro Flasks offer improved insulation over the classic Hydro Flask. The new cap not only offers improved insulation, but also a handy carrying strap! These new Hydro Flasks feature a range of new colors to select from. Check out the Flex Cap Wide Mouth Hydro Flask on Amazon and be sure to read our review of the Flex Cap.
Hydro Flask may also take the crown for the title of most customizable insulated water bottle. With the huge range of models on offer featuring a variety of sizes, colors, designs, and accessories, even “stock” Hydro Flasks can be quite unique from one another. But they have stepped things up with the MyHydro Program, which allows you to create a create a completely customized Hydro Flask from scratch, selecting your design, color, and a range of other options. You can even create a variety of Hydro Flask unique to the MyHydro Program, so you know you’ll be the only one sporting it!
The YETI Rambler Bottle was our top performer in our hot water insulation tests by a wide margin. We’re not entirely sure why the YETI Rambler bottle seems so much better at hot insulation than cold, but it performs admirably at both. The YETI is a serious contender for the title of Best Insulated Water Bottle, and for awhile during our testing it looked like we would be crowning it the victor.
YETI Rambler bottles are made from the same company that makes the highly popular YETI Cooler, so these folks know a thing or two about insulation. It shows in the bottle’s top-notch construction and top-of-the-line insulating capabilities. Not only does the Rambler provide a brilliantly functional bottle, it has a sleek modern look and a selection of pleasing colors to choose from.
Ultimately, we gave the title of Best Insulated Bottle to Hydro Flask largely on account of it being more affordable than the YETI Rambler. The Hydro Flask also performed marginally better than the YETI Rambler in our cold water insulation test, but the YETI Rambler took a substantial lead in our hot water insulating test, leaving all the competitors lagging behind. If you’re interested in more one-on-one comparison with Hydro Flask, read our Hydro Flask vs. YETI Rambler Comparison.
Want to learn more about what we have to say on the YETI Rambler Bottle? Be sure to read our complete review.
S’well Bottles have taken the water bottle world by storm. Immediately appealing to just about everyone, the innovative and artful designs of these bottles defy convention and have stunning options that leave you hardly able to believe you’re looking at a stainless steel bottle. It was all this eye-catching pizzazz that led us to name S’well Bottle the Best Water Bottle of 2017.
And it is quite a bottle to use, as well as to behold. In fact, the S’well is the only insulated bottle we tested with Triple-Wall Vacuum Insulation. This utilizes the same Double-Wall technique we talked about above, but incorporates an extra layer of copper in between to, in theory, improve insulation further. As you can see above, in our tests the triple-wall insulation did not outperform the double-wall designs of our other insulated bottles.
Regardless, as demonstrated in the insulation tests above, the S’well Bottle gives even our best insulated water bottles a run for their money. While it lags behind a bit in some of our testing, the bottle more than makes up for this with its unique style and ergonomic form factor. Anyone with an eye for fashion — or just plain old cool stuff — will be able to appreciate the beauty of a S’well bottle.
If you want to see how the S’well Bottle compares to our #1 pick, the Hydro Flask, read our Hydro Flask vs. S’well Bottle Comparison.
To get more on just the S’well Bottle itself, be sure to have a read through our complete review of S’well Bottles.
In our feature “Hydro Flask vs. Klean Kanteen: The Great Insulated Debate” we tried to settle the score once and for all between Hydro Flask and Klean Kanteen, yet here we are once more forced to pit them against one another.
In insulation, the Klean Kanteen stands up to every competitor proudly. Our test showed it providing reliable middle-of-the-road results always just on the heels of the best performers in every insulation test. Like the rest of the bottle, the insulation is steady and reliable.
The Klean Kanteen has definitely earned its place as one of the top insulated bottles on the market. They are incredibly durable – so much so that rugged campers have even demonstrated the ability to boil water in them with no harm to the Klean Kanteen. As far as insulation capabilities go, it is definitely one of the best insulated bottles on the market. Klean Kanteens are available in just about every size, and there are a huge number of colors and artwork available.
One of the most affordable and well put-together insulated stainless steel bottles to come on the market in the last few years, we’ve highlighted the Thermoflask as a viable budget Hydro Flask alternative. But the Takeya Thermoflask is more than just a knock-off: it is a serious competitor.
With a generous 40-ounce capacity, a tried-and-true design which reflects the best insulated bottles on the market, and an insulating capability which can stack up to top brands like Hydro Flask and Klean Kanteen, the Thermoflask is nothing to shake a stick at. This makes its incredible bargain price tag even more impressive, earning it the distinction of being the best bargain insulated bottle on this list.
Constructed from 18/8 food-grade stainless steel and backed by the reliability of the Takeya brand, a 2-pack of Thermoflasks runs only about $40, making two of these bottles comparable to the price of a single Hydro Flask. In terms of durability, functionality, and even appearance, the Thermoflask stacks up to the competition remarkably well.
Learn more by reading our complete review of the Takeya Thermoflask or check current prices and find other details by visiting the Amazon listing.
The FNova Insulated Stainless Steel Bottle is among a growing trend of products which are, in form and in function, essentially generic Hydro Flasks. As we have recently been discovering here at Hydration Anywhere, this appears to be a great trend for consumers. The FNova bottle is a great example of how that can take shape. Offering exceptional value for the money, the 35 ounce FNova is comparable to a Hydro Flask in almost every way yet almost $10 cheaper than a comparable 32 ounce Hydro Flask.
The FNova isn’t quite as well-built as a Hydro Flask, and as we seen in the insulation test it performs slightly below the Hydro Flask’s insulating capabilities. Regardless, it offers an exceptional value for the money, especially when the inclusion of two different lids (a flip-top “sports cap” and a plastic screw-on lid with handle,) along with a neoprene carrying pouch, the FNova is a real bargain and exceptional quality considering the price.
Learn more in our complete review of the FNova Insulated Stainless Steel Water Bottle or visit the Amazon listing. Also check out the FNova’s larger 40oz model the FNova Flask in our complete review of the FNova Flask.
The Fifty/Fifty Vacuum Insulated Water Bottle offers another affordable generic bottle in the style of Hydro Flask. Made from 18/8 food-grade stainless steel, the Fifty/Fifty bottle is a winning iteration on this ubiquitous modern stainless steel bottle design. While it doesn’t try much for anything in the way of innovation or extra features, the Fifty/Fifty provides a high-quality insulated bottle at a very agreeable price.
Fifty/Fifty offers exceptional insulation and quality manufacturing. Unlike some of the cheaper generic Hydro Flask bottles you might find at the bottom of the bargain bin, Fifty/Fifty bottles are mid-range in price and the quality definitely is reflected in the product. Solidly constructed, no-nonsense design, highly functional insulation, and a huge range of sizes and colors, Fifty/Fifty brings a lot of options to the table and is definitely one of the top options for insulated stainless steel bottles.
Learn more by visiting the Fifty/Fifty Water Bottle Amazon listing.
(UPDATE: Check out our complete review of the 40 ounce Fifty/Fifty Insulated Water Bottle!)
While I’ve never thought of a Thermos as a “water bottle” per-se, it turns out that Thermos actually does make water bottles. Not only that, your average Thermos is renown for being an insulated bottle, even if we might more commonly associate them with holding soup than water, they are really just as capable of doing the insulating job as any other insulated stainless steel bottle.
But if you want an actual, sleek, modern water bottle, the Thermos has you covered for that, too. This bottle has a very stylish look and performs admirably at keeping the contents more or less the exact temperature at which you put them in.
Thermos actually have quite the range of insulated bottles and classic Thermos bottles. Check out some of the options in our Best Thermos Bottles Guide!
You can also learn more by visiting the Thermos Vacuum Insulated Stainless Steel Water Bottle Amazon listing.
Of all the insulated stainless steel bottles we’ve come across, only the refresh2go Excursion has included a filter straight out of the box. Sometimes, it’s hard enough to find an insulated water bottle with a straw, but the refresh2go excursion includes one integrated into its filter. The filter itself is just a simple activated coconut shell carbon filter. It can clean up the taste of your tap water, but it can’t make non-potable water safe to drink. But if you want to get rid of common tap water contaminants, remove sediment, and tame the taste of chlorine, these filters do a great job.
In terms of insulation the refresh2go excursion is not bad. Like any insulated bottle with straw cap, it suffers a bit of heat loss from the nature of the straw lid. The refresh2go excursion didn’t make the cut for one of our best insulated bottles on insulation capacity alone, because there are certainly bottles that can outperform its insulating ability. However, few of them have a filter. And the insulation this bottle does perform is plenty admirable.
For the full run-down on refresh2go insulated water bottles with straw filters, have a look at our complete review.
Compared to the insulated bottles above, this Cayman Fitness Premium Water Bottle is from a relatively unknown brand. However, it is a very well designed bottle geared towards ease of portability and usage while on the go. It fits easily into just about any cupholder, providers a brilliant leak-proofing which lets you carry the bottle without fear of a spill, and has a simple yet stylish look.
In our day-to-day evaluations we’ve found that it is also a contender capable of stacking up to the market leaders when it comes to keeping colds cold and hots hot. The Cayman Fitness bottle does not benefit from the wide variety of options offered by Hydro Flask or Klean Kanteen, instead having only a single 17 ounce bottle. However, we have found it to be an exceptional bottle, so perhaps no variations are necessary. The only complaint we can lodge against the Cayman Fitness insulated bottle is its lack of a wide-mouth option and a very narrow mouth, which can make putting ice in very difficult.
Learn more in our complete review of the Cayman Fitness Insulated Water Bottle or visit the Amazon listing.
So Many Bottles, So Little Time!
In my opinion, and in the opinion of everyone here at Hydration Anywhere, the best insulated bottles around are either Hydro Flasks or Klean Kanteens. But we respect the fact that this is a subjective opinion, and more than that, there are now so many dozens upon dozens of insulated bottles on the market from so many different manufacturers that trying them all is almost impossible.
We feel confident that anyone looking for an insulated bottle would be happy with any of the selections we’ve pointed out in this article. Take some time to select the bottle which best suits your needs and everyday lifestyle. Think about where the bottle will be accompanying you, if you want it to fit into a cup holder, how much water you really need to be carrying around, how much you drink in a day, and other considerations to help guide you towards selecting the best option.
What’s YOUR Pick For Best Insulated Bottle?
Did we miss your favorite brand or model on this list? Have a suggestion for something completely different? We’d love to hear from you in the comments below! Or if you didn’t find what you were looking for in this list, check out Best Water Bottles 2017, Best Water Bottles 2016 or even Best Water Bottles 2015 to get some more ideas. If you’re sure you want quality insulation but were hoping for something a little bigger than the options on this list, read our article on the Best Insulated Growlers!
We are nowhere near done reviewing insulated bottles! Keep reading for the latest on new bottles. Check back to our Reviews Section, or signup for our newsletter to get regular updates on what’s up at Hydration Anywhere. You can also follow us on Facebook, Twitter, or Pinterest to keep track of what we’re up to. Thanks for reading!
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We explain the best type of insulation, and examine the best brands and models of insulated water bottle.
Jacob Hatch is the author and founder of Hydration Anywhere. He has been actively writing about drinking water since 2013. These days Jacob spends most of his time investigating water related news, studying environmental issues, reading health studies, and reviewing products like water bottles and water filters.