Insulated water bottle

Insulated water bottle reviews on kleen kanteen on specific temperatures

the manufacturer mention that they keep cold or hot liquid for a period of time wondering if any actual test has been conducted to see how true claims are.


If they are like the ones we have, they are a thermos flask made of stainless steel and work brillintly.

My wife filled our first one with tap water and put it in the fridge.

She was surprised taht the water had not cooled at all when she tried it many hours later.


Yes apparently are double wall. I was wanting to see if any have been tested for either cold or heat specific to heat as they mention it retains the temperature upnto more than 2 days. I couldn’t see any posts about flasks test


Do others remember studying how insulated flasks work in junior science class?
To address heat loss by

  1. radiation
  2. convection
  3. conduction

The most efficient ones have:

  • double wall
  • inner vessel is made of a material that does not conduct heat well, for example glass (and definitely not metal)
  • the inner vessel has reflective surface (like a mirror) to reduce heat loss by radiation
  • the space between the inner vessel and the outer vessel does not contain anything, that is, it is a vacuum (so no convection)
  • the bottom of the inner vessel is supported by a small piece of non-conductive material, for example cork
  • the top of the inner vessel is joined to the rest of the insulated flask by a membrane/gasket that is non-conductive and strong enough to keep air pressure out of the vacuum between the inner and outer vessel.
  • the stopper is made out non-conductive material to reduce heat loss by conduction (and stopper is often hollow with vacuum to reduce heat loss by convection).
  • the outer vessel is robust to withstand knocks, and to protect the vacuum and the inner vessel.

Most of those attributes require you to take the thing apart to verify. Testing actual performance would be more accurate and likely easier. What do you do if your flask lacks one of these qualities, what effect would it have on performance? There is no way to know.

I for one would not like to go back to the days of glass vacuum flasks regardless of any supposed increase in efficiency. They had three layers, the actual vacuum flask was all glass in both walls and this was supported inside an outer metal sleeve. No amount of robustness in the outer cover would save the inner flask if it got a good knock or (heaven forfend) it was dropped. The stainless steel two wall flask was a great advance.


Could you use a thermometer to test the water temperature. I had thought but them the cap would have to be off to test it loose heat


One of my 600ml Camelback insulated flasks, made from stainless steel, certainly keeps water cool for over 36 hours in summer in a warm house with no AC cooling. Starting with ~300ml water and 300ml ice, the water is still cool 36+ hours later, with ice still being present after 24 hours, kept beside the bed.
I have 1200ml insulated Camelback flasks too, which keep water cool all day in hot summer weather, when starting with about half ice/water.


You can, it will take a little patience but it is quite doable.

Fill the flask with ice water (no ice) and put the lid on, wait 5 minutes. Take the temperature and replace the cap. Every few hours take the temperature again and replace the cap. To avoid having to take the temperature at set intervals record the time and temperature and graph the result. The values will rise in a curve tending to level out with time.

You will gain a little heat each time you open it but not enough to worry about. The main variable will be the fluctuations in ambient temperature so ideally the room would remain the same but that is hard to arrange. Still this will give you a good idea of your cold drink will still be cold tomorrow or the day after.

You can do the same with boiling water, you will get a similar curve only the other direction.

My bet is that comparison of different makes or models would not be a big difference unless one is faulty and the vacuum has failed. There are models that are not vacuum flasks but use foam insulation, I reckon they would be measurably inferior.

The part the domestic user has a problem with is buying a few dozen brands to compare :smiley: You could give them as Christmas presents when you are finished.


How about boiling water. I purchased onr because traditional plastic or steel water bottles dont insulate in hot weather as i found once in hot weather at work. The insulation keeps the water cold instead of going hot… Kleen kanteen say that hot water remains hot for several days

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I’ve never tried it, not being a drinker of hot water drinks, but vacuum insulation works both ways, so I don’t see why it wouldn’t keep it hot for at least 12 hours. The temperature differential is much greater for hot water to ambient vs cold to ambient, so the rate of temperature change for the hot water is no doubt greater.

I wonder what Kleen kanteen’s definition of ‘hot’ is, to support the several days claim.


Is it also worth considering that not all water flasks are genuinely ‘vacuum’ flasks. They may simply be a stainless liner in a an outer casing of metal or plastic. ‘Insulated’ is an open ended claim.

Should any review or testing look at the labelling and marketing promises?

Keeps water cool or hot for up to 24 hrs could be claimed by many flasks/containers. It’s not a reliable measure of performance or promise one might be able to disprove. How does one really know how effective a product is prior to purchase?

Great OP @passerbye123. :+1:


Yes true i do not know if they test them for a period or not for reliability.i just had a quick look at the website it is clear in saying hot for 24 hours /cold 90 hours

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We conducted a test in 2019. The article [member content] is here: Insulated water bottle

That link is back to this topic :smiley: I presume you meant this test? Or was there another?


Good grief. It’s one of those mornings. Too little sleep due to strong winds damaging the bedroom windows…

Yes, I meant to point to that article. Thanks Phil !


Thanks for the information on the bottles. I tell you i would be missing out on buying the kmart one after the comment saying it left a metallic taste. Anyway a good review once again.


I have avanti for cold and have another brand I use for hot drinks. works well when Vivid is on.

used the thermos one for icy cold coffee and it kept cold for hours.


I used my black kleen kanteen today and was sitting in my car for several hours the water was warm. Im not sure if that is viable considering they say keep cold for many hours. This wS, a good test. I am not sure it reliable

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