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ThermoFlask is a water bottle brand that’s been gaining popularity recently. Its main selling point? An affordable price for a solid set of features. It’s definitely not a one-trick pony, and I really appreciate its versatility.
While it might not match the overall performance of top-rated bottles, especially in terms of insulation, it’s a great budget-friendly alternative.
In this review, I’ll reveal everything you need to know about ThermoFlask and dive into what makes this bottle worth the price.
Insulation
There’s a great word that describes the insulation performance of the ThermoFlask: “decent”.
It does a respectable job at keeping your water cold for 24 hours (thus the logo, I assume!), though not quite as cold as some high-end competitors. Its heat retention, however, falls short.
Cold Retention Test
ThermoFlask promises to keep your water cold for 24 hours, and in my experience, it mostly delivers on this front.
During my test, I started with chilled water at 32°F (0°C) and left it out in room temperature for 24 hours. By the end of the day, the water had warmed up to 55.9°F (13.3°C).
Not bad, but I’ve seen some other bottles keeping my water a few degrees colder over the same period. That said, you can still count on the ThermoFlask to keep your water cold-ish for a full day.
If you want to maximize its cold retention potential, just add a quarter of the bottle’s capacity in ice.
Heat Retention Test
Heat retention is where things get a little less rosy. ThermoFlask claims to keep your beverages hot for 12 hours, but my tests tell a different story.
I filled the bottle with hot tea at 203°F (95°C) and waited for 8 hours. When I came back, the temperature had dropped to 118°F (47.8°C), which is way below what I’d consider “hot.” For reference, the lower threshold for hot drinks is around 122°F (50°C).
So, while the ThermoFlask can technically keep your drink warm, it’s not going to stay piping hot beyond 6 hours.
This is a bit disappointing, especially compared to other bottles. Hydro Flask and Iron Flask, for instance, can keep your beverages hot for almost twice as long. In fact, Iron Flask boasts an impressive 17-hour heat retention.
ThermoFlask, on the other hand, leaves you wanting more warmth after just half a workday.
Insulation Score
★★★★☆
Lid Design
The ThermoFlask’s lid is more functional than flashy and uses the same popular design you’ll find in Takeya Actives and some other water bottles.
It’s a one-piece lid with the cap and handle attached, which is fantastic for someone like me who tends to lose smaller parts.
One feature I particularly appreciate is how easy it is to open and close this lid. There’s even a removable rubber band with the ThermoFlask logo that provides extra grip when you’re trying to unscrew it.
The cap itself is straightforward, just how I like it. It requires three simple movements to unscrew and then a gentle pull upwards to access the spout, which offers a comfortable drinking experience. It feels natural and doesn’t require any weird contortions or awkward angles to take a sip.
While the ThermoFlask lid may not win any innovation awards, it certainly scores high on practicality and ease of use. Sometimes, being “decent” is exactly what you need from a water bottle lid.
Lid Design Score
★★★☆☆
Durability
ThermoFlask’s body is made from premium 18/8 stainless steel, which is durable and can take a hit or two without turning into a dented mess.
However, it doesn’t quite reach the level of my most durable bottles like Hydro Flask or YETI Rambler. You can feel the difference immediately; those brands have thicker walls that scream “built to last.”
ThermoFlask, while sturdy, feels a bit lighter and less rugged in comparison.
What sets the ThermoFlask apart is its removable silicone boot (available only if you get the 2-pack). This little addition adds value and prevents annoying dents and dings that inevitably happen when you drop it on unforgiving surfaces.
The lid itself is also decent in terms of durability. It does the job without any drama, but I do have some reservations about the handle.
Made from thin plastic, the handle bends very easily, which makes me worry that one day it might just snap off when I least expect it. It’s connected to the lid with a small piece of metal, and while that metal hasn’t failed me yet, it doesn’t inspire a whole lot of confidence.
Overall, the ThermoFlask’s durability is on par with other stainless steel bottles. It’s tough enough for daily use, provided you handle the handle (pun intended) with some care.
Durability Score
★★★★☆
Portability
First things first, if you want to use your ThermoFlask in your car and take it on road trips, keep in mind that not all of the sizes will fit in your cup holder.
My 24 oz. ThermoFlask, with its 3.1 inches in diameter, barely fits in those tight spaces. If you prefer larger sizes, I recommend measuring your cup holder first to make sure it’ll fit.
Weight-wise, ThermoFlask isn’t the lightest contender in the stainless steel bottle arena as my 24 oz. version weighs in at 14.1 ounces. Is it featherlight? Nope. But does it bother me much in my daily life? Not really.
I’ve carried heavier things without breaking a sweat, and this bottle doesn’t tip the scales into unbearable territory.
What about carrying the bottle? ThermoFlask has made a thoughtful improvement by giving their handle a bit more size compared to other bottles with similar lid designs. The result? A more comfortable carrying experience.
You can fit even four fingers through it, which is a rare and super useful feature.
Portability Score
★★★★☆
Leakproofness
ThermoFlask is definitely a leakproof bottle, as long as you close the lid and, more importantly, the cap properly.
This is true for most water bottles, but ThermoFlask demands a bit more attention to detail when it comes to screwing the cap on correctly. If you leave it even slightly unscrewed, it’ll probably leak a lot.
This happened to me before with my Takeya Actives bottle, which have the exact same cap design.
Leakproofness Score
★★★★☆
Ease of Cleaning
Cleaning my ThermoFlask manually has been easy because of its simple design.
There are two gaskets, though, in the lid and cap that you ideally want to remove occasionally to clean them thoroughly.
While taking out the gasket in the lid is easy, removing the one in the cap is trickier and requires a small tool. But that doesn’t take away from how easy this bottle is to clean.
And did I mention it’s dishwasher safe? It absolutely is, so you can save even more time getting your ThermoFlask spotless.
Ease of Cleaning Score
★★★★★
Versatility
The versatility of my ThermoFlask is on a good level, and I like taking it to many places and for many activities.
Thanks to the combination of decent insulation performance, durability, and portability, it doesn’t bother me much and it doesn’t get on my nerves when I do a lot of moving around, unlike some other bottles (looking at you, YETI Rambler).
In more stationary settings, it works equally well. Taking it to the gym or work is not a problem either. It’s sturdy enough to survive the gym locker room and sleek enough to sit on my desk without looking out of place.
The insulation keeps my water cold during grueling spin classes and my tea warm through endless Zoom meetings.
My only gripe is the size as sometimes I find my 24 oz. ThermoFlask to be not enough. If hydration is a priority, go for the 32 oz. capacity. It saves you the hassle of multiple refills and makes the bottle even more versatile.
Versatility Score
★★★★☆
Price/Value Ratio
Getting great value for your money can feel like scoring a deal at a yard sale, and that’s exactly how I felt when purchasing my ThermoFlask.
Actually, I got myself a two-pack of 24 oz. ThermoFlasks for which I paid $36, which breaks down to $18 per bottle. This is an amazing price for the value you’re getting with this bottle.
If you’d like just one, it’ll cost you $25. So, if you’re thinking of giving one as a gift or simply want two bottles for yourself (everyone needs a backup), the two-pack is definitely a cost-effective option.
What makes this deal even sweeter is that ThermoFlask products come with a limited lifetime warranty against manufacturer’s defects. Knowing that you have this safety net in place makes you appreciate the value of the bottle even more.
Price/Value Ratio Score
★★★★★
Conclusion: Is ThermoFlask Worth the Money?
ThermoFlask is a very decent bottle that you’ll find worth the price. It provides a solid combination of important features, including decent insulation performance, durability, portability, ease of cleaning, and leakproof capabilities – all for a reasonable price compared to other stainless steel bottles.
However, if you’re looking for something a bit more unique in the same price range, I’d also consider the Owala FreeSip. And if insulation performance and durability are your top priorities, the CamelBak Chute Mag makes an interesting alternative.
WBA Test Results
How we test products
Every product we review is tested using the same structured process, with dozens of measurements and checks covering areas such as thermal performance, lid usability, cleaning, durability, portability, and everyday use. Those results feed into the WBA Score, which helps us compare bottles using consistent criteria instead of relying only on manufacturer claims.
You can read our full product testing protocol, learn more about Water Bottle Advisor and how we test products, or see how the WBA Score works.
About the author
Jeremiah Kowalski
Jeremiah Kowalski founded Water Bottle Advisor to make drinkware reviews more useful and less dependent on manufacturer claims. He has personally tested 50+ products, putting them through measuring, cleaning, leak testing, durability testing, and everyday use before sharing his conclusions. It also means occasionally explaining why yet another large box of bottles has arrived at his door.
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