How well do they keep things cold or hot?
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24 ounce Bubba Hero |
We have a number of these around our house, so I decided to test them. This is the 24 ounce Hero Bubba water bottle. I tested it cold and hot. I Got a very similar time constant for each, as you would expect.
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20 ounce Bubba Hero |
This is a grocery store variety 20 ounce
Bubba Hero. I think it was less than $15 this year.
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24 Hours |
This is a very good
smaller vacuum flask that I got as a gift from my daughter about 10
years ago. It does extremely well for a 16 oz flask.
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REI Vacuum Flask |
This is a very nice
vacuum flask that I have had for about 20 years and it is still the
best.
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Air Insulated Eater Bottle |
This is an air-insulated
16 oz. water bottle that I got in Los Angeles a few years ago. It turns
out this is a pretty good water bottle for the money. However, don't
expect it to work like a vacuum flask. It only has a hold time of two
hours.
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I use these vacuum insulated mugs for my iced tea
constantly, so I thought I would test these, also.
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My wife and daughter love these Hydroflasks, so there
was no question that I would test these.
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Someone suggested that Mira bottles were as good as
Hydroflask at half the price. So I got a couple and tested them. The
results varied, but they were certainly in line with Hydroflask.
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We went to Moab and ended up with several of these flasks. I may get around to testing them. |
By the way, if you are really sharp, you have noticed that there is a glitch in the thermometer at 90, 110, 130, and 150 degrees Fahrenheit.
A cheaper vacuum flask may be pumped down to a good vacuum (10-3 torr) but it is probably not coated internally with silver for low emissivity in the wavelength band 1 micron to 20 microns. For reference, bare stainless steel has a lot more emissivity than silver in this band, as shown in the next figure. Even aluminum would be far better than stainless steel. My guess is that the Bubba flask is either coated with aluminum or not at all.
Bill Otto
Last Updated 03/03/2020
