Air conditioning you can wear: Our guide to personal cooling devices

The heat just keeps on coming.

Earlier this month, the world experienced its warmest day. And that was on the heels of the hottest June on record. That made us wonder how to beat the heat, aside from just retreating indoors and cranking up the AC.

Luckily for us, scientists and inventors have been working on personal cooling devices — gadgets and garments that promise portable climate control.

Last year, the U.S. Department of Homeland Security held a Cooling Solutions Challenge, which provided funding for things like biomimetic textiles, which are inspired by the way fur keeps camels cool. And research at Stanford University brought us the CoolMitt, a portable, rechargeable device designed to cool the body's core by having the user wear a liquid-chilled mitten. The device, touted for athletes, soldiers and firefighters, costs $1,499. Shipping is free.

That's a little bit beyond our budget. But we did find a handful of more affordable gadgets that promise to provide wearable relief from the heat.

To test them out, we contacted Seigo Masubuchi, a St. Paul resident and veteran marathon runner who knows a little bit about being hot. Masubuchi, an "ushertainer" with the St. Paul Saints baseball team, once ran the Twin Cities Marathon wearing a furry 18-pound costume of the Saints' mascot, Mudonna.

"I sweated like a pig," Masubuchi said.

Here's his assessment of some cooling devices we found on Amazon:

Byrotson solar fan sun hat
$59.88
What it is: A big floppy hat with two fans in the brim that blow air into your face.
Pros/cons: The rechargeable batteries provide a much more reliable breeze than the built-in solar cells for power. But it's hard to adjust where the wind blows, the fans are a bit noisy and you can feel the vibrations on your head.
Seigo says: "The fan feels good." He would have liked to have had it when he wore the Mudonna costume.

KAOJMUQ neck air conditioner
$46.99
What it is: One of the many battery-powered gadgets that you wrap around your neck to blow air.
Pros/cons: This one has three speeds and also features a couple of metallic pads that press against your neck for a "cold compress" effect. It does make your neck feel cool, but like the fan hat, it's a bit loud on the highest speed.
Seigo says: He found the fan hat more cooling. "Right now, I'm just feeling pressure on my neck. Maybe once I got used to it this would be good."

Black+Decker Comfortpak
$99.99
What it is: Has a prankster ever dropped an ice cube down the back of your shirt? Now you can try to replicate that chill-down-the-spine feeling with a battery-powered gadget.
Pros/cons: The palm-sized device hangs from your neck like a pendant, except its cool metal plate is worn on the back, so it presses between your shoulder blades. If you flip a switch, it also will provide warmth. It may be better at generating heat than cold, but at least it's quiet.
Seigo says: It didn't bounce much when he ran with the device, but "I don't feel much cooling benefit," he said. "I don't think I'd buy this thing."

Bgulong portable waist fan
$49.99
What it is: You may have flapped the bottom of your shirt to blow some air on your torso on a hot day. Now you can let a rechargeable waist fan do it for you.
Pros/cons: It has three fans and a battery mounted on a stout belt. Clips hold your shirt's hem so the fans can shoot the air upwards. Generates a decent breeze, but it's heavy and cumbersome.
Seigo says: "The first reaction is 'Wow, I'm feeling the air!' It's too heavy to wear running, but it would work well for walking or yard work.

ARRIS 5V fan jacket
$38.98
What it is: A light, short-sleeved jacket with a couple of fans built into the back. When you plug in a battery-pack (not included), the jacket inflates and vents out the neck and sleeves so you have a constant flow of air around your torso.
Pros/cons: People may wonder what's that noise you're making. They may also ask if you've gained weight when the jacket puffs up. It's not for everyone: The instructions warn against using it if you're pregnant or have a pacemaker.
Seigo says: "The air is circulating. It's something to get used to. I don't see myself wearing this, but I see the purpose."

HJDHS evaporative cooling vest
$39.99
What it is: Unlike cooling vests that use ice or gel packs, fans or battery-powered cooling plates, this one relies on evaporation. It's made of an absorbent PVA material commonly found in sports towels. You just soak it in water for a few minutes and the evaporation is supposed to keep you cool.
Pros/cons: Quiet and simple to use and reuse. It doesn't require batteries or a freezer. It does help you feel cool, but also clammy. The one we got didn't have a way to close the front of the vest. Maybe it would work better if you combine it with the fan jacket.
Seigo says: "It's cold. This is very cold." Not for runners, but it might be just the thing for construction workers, mail carriers or anyone who has to work in the heat.

Final analysis

No matter how good these products might be, they can't replace the most fundamental tools for coping with high temperatures: staying hydrated, reducing exertion, getting out of direct sunlight and getting into an air-conditioned environment.

If you get a headache or stop sweating when exposed to high temperatures, those are warning signs that you may be overheating, said Dr. Nicholas Simpson, an emergency medicine physician with Hennepin County Medical Center.

Confusion, nausea and inability to keep down liquids to rehydrate may be signs of a heat stroke that requires medical attention.