it should be indicated on the container somewhere if it has been manufactured by a known reputable brand sold in the United States. If the capacity is the same, & the exterior dimensions are both the same, then it's dark magic that makes the capacities the same. i just lug plain w/e temp it is water along to chug. The hassle is not for me to bring a gourmet beverage.

camel bak with ice. works well in central Texas in august.

I have a couple of those larger Podium Chill bottles. I like them. Beyond the insulation factor, I like the hands free spout. It’s easy to pull out the bottle, drink and put it back while riding, all with one hand.

Otto

two water bottles, one insulated, one uninsulated
Pictured above are two water bottles, insulated on the right, uninsulated on the left. Both bottles are labelled 750 mL (no, I didn't measure the volume; I'll assume they're close enough to labelled volume to not matter). The insulated bottle is approx. 5/8" taller than the uninsulated one. So yes, there is a difference in the size of an insulated bottle vs uninsulated of the same volume (and by extension, bottles of the same external dimensions will have different volumes). For me, the difference isn't enough to matter (if you have a small main triangle or use a frame bag and bottles are a tight fit, that 5/8" might make a difference).

As far as the effectiveness, I find that when I start out with a bottle filled with ice and topped off with cold water on a west Alabama summer day (90-100F temp, high humidity), after about 3 hours the insulated bottle isn't cold anymore, but it is still noticeably cooler than ambient temps. I don't usually bother to freeze bottles the night before, so I can't comment on how much more effective that might be compared to just filling with ice.

Size (i.e., length) was not something my comment was concerned with. Capacity (i.e., volume) was. My 25 oz. insulated bottles fit in standard cages. One reason the brand is very popular.

I use those.

Our local C-store chain has 32 oz drink specials during the summer. With ice they are good for 30 minutes max. If i slip them in a small plastic bag like they have for hot dogs, the ice lasts twice as long.

Right. And if the same volume in an insulated bottle requires a larger size, then an insulated bottle of the same size will have a smaller volume.

For me, the difference isn’t enough to matter, and I happily use insulated bottles.

If someone really wants to know how much less an insulated bottle holds compared to an equally sized uninsulated bottle, they should be able to calculate the difference. I think they’re close enough to not worry about it.

I do that also. I bought insulated lunch box with sleeves which are frozen night before. They hold around 3 water bottles.

One has a handle strap which goes over the handle bars.

The problem I have is with actually taking a sip before the drink is warm. Expecting the drink to remain cold for much more than an hour in hot conditions is maybe expecting too much, at least for me.

Kevin g