Let’s face it. When you’re on a roadtrip, you need to sip on something. I used to be on the what comes in, has to go out, theory. When I have to stop, I restock. And keep the soda cold in a thermos.
I’m retesting my methodology under the category of cost-effectiveness. So first, I need to test how long each method keeps ice. Ice keeps the contents around 32deg. Then determine the amount of money spent on each container.
There are other considerations such as keeping a large ice chest secured and accessible while driving, but we’re not considering that now.
How long does ice last in a small cooler?
Ice chest, 30qt, $30
5/30, 10p, 4lb of ice, fully packed product. No room for foam cap. Retry tomorrow am. Expect 4 days w foam cap. next 2 days in 70deg weather in Sequoia.
6/3, 1oa, 3.5 days, still ice. Last 24 hours in Fresno, 90+deg weather.
How long does ice last in a thermos?
Vacuum bottle, 750ml, $20. Expected with 50 pct ice, 3 days fully melted, in Phoenix then Flagstaff.
5/18/2017, 3:30p, 2/3 of ice, approx 500ml.
5/19, 1p, most of the ice seems there.
5/20, 10a, still ice
5/21, 10a, no ice, but water still chilly. 1/3 full so 250ml.
Metric: $/lb of ice*hr
Surprisingly. The cooler is more cost effective in the long run bc ice and soda from a supermarket is much cheaper, than even my favorite Super Big Gulp 40oz from 7-Eleven.
The thermos can keep a small amount colder, longer bc it’s better insulated, but ice is cheap. You can buy 10lbs of it for $2, which will last 3 days. Twice as long as your beverage will stay cold inside a small thermos.
To measure effectiveness of temperature maintenance at at 40deg F or below
lb of ice / hr. As long as there is ice, the water should be 32deg. But in a cooler, not everything is under ice.
To measure the hit on your wallet
$(of 1L of beverage + ice) / day
Strangely, buying soda from a gas station, and filling your thermos with it every day costs more than buying a cooler, 4L of soda for $3, and 20lb of ice, every 4 days.
If you cheat a little at fast food restaurants, you can pay a little extra cents for the large soda, fill up at the fountains before you leave, and fill your thermos to keep it cold.
As for thermos quality, if your thermos sweats, you probably need a better thermos. My 500mL thermos.