Comparing the StaCool Under Vest to Evaporative Vests and Paraffin Vests

Over the years, there have been many approaches to achieving body cooling for those who are unable to sweat due to a physical condition or people that have multiple sclerosis (MS) and have a high intolerance to heat. In today's body cooling market, cooling vests are a well-established and popular passive cooling technology.

However, all body cooling vests are not equal. There are various designs and styles to choose from, as well as various cooling technologies. This article takes a closer look at three cooling vest types: Evaporative cooling vests, Paraffin cooling vests, and the StaCool Under Vest.

Evaporative Cooling Vests

Evaporative cooling vests are the simplest to make and most basic in function. These vests are made of cloth materials and provide cooling simply through the evaporation of water, similar to body sweat. The water absorbs heat from your body, and under favorable air conditions, that heat vaporizes the water into the atmosphere.

To use evaporative vests, you must immerse them in water before putting them on. Although some of the vests are lined with a water repellant liner, the vests are not waterproof. So, users often complain that their clothes get wet while wearing these evaporative vests.

In addition, these vests are not very effective if worn beneath clothing. So, some evaporative vest weares say they feel silly or embarrassed walking around in an unstylish or industrial-looking vest. Others complain the vests are heavy and feel soggy.

Perhaps the biggest limitation of the evaporative vest is that it cannot provide cooling in high heat and humidity conditions.

There is a limit to how much moisture the outside air can absorb, based on temperature and pressure. Once air has reached this limit, as is the case in humid environments, it is completely saturated and cannot absorb any additional moisture. In this situation, an evaporative vest is practically useless, as the water it holds cannot evaporate into the air.

Paraffin Cooling Vests

Paraffin vests rely on a slightly different mechanism than evaporative vests for cooling. Simliar to water evaporation, paraffin vests use the physics of phase-changing to provide cooling. But instead of changing liquid water to water vapor, paraffin vests change solid paraffin wax to liquid paraffin wax.

This is an effective cooling method, because it takes a significant amount of energy to change the phase of any compound. The paraffin vest works by absorbing heat from your body and using that energy to essentially melt the wax. When the wax has melted, you need to replace the wax packs or change into another cooling vest.

Shortcomings of the paraffin cooling vest include short cooling times and flammability. Paraffin is flammable, so that makes paraffin cooling vests undesirable for people who work around open flames such firefighters or chefs. Paraffin cooling vests may also be a poor choice for people who have an increased risk of being in accidents involving fire, such as motorcycle drivers.

The StaCool Under Vest

Unlike the paraffin cooling vest and the evaporative cooling vest, The StaCool Under Vest does not rely on evaporation or melting to provide body cooling. Instead, the StaCool Under Vest uses an advanced polymer cooling material that can absorb large amounts of heat energy.
This advanced cooling material is injected into several isolated chambers inside a StaCool ThermoPak, providing redundancy and a wide cooling area. The ThermoPaks are prepared for use by placing them in a typical kitchen freezer. Then, they are inserted into pockets within the StaCool Under Vest when body cooling is needed.

Unlike water, the cooling material inside each ThermoPak  remains flexible and does not freeze into a solid form. This provides great flexibility and freedom of movement for the StaCool Under Vest user, a benefit that cannot be duplicated by vests using simple ice packs.

In contrast to evaporative vests, the StaCool Under Vest may be worn beneath or over clothing, and it does not get your skin or clothes wet. And unlike paraffin vests, the StaCool vest is not flammable, so it is completely safe for any work or recreational environment. The StaCool Under Vest is also completely non-toxic.

In terms of body cooling time, the StaCool Under Vest can provide up to 3 hours of cooling before the ThermoPaks need to be replaced or re-cooled. This makes it more effective and longer-lasting than either the paraffin vest or the evaporative vest.

A Body Cooling Vest Summary

Here is a quick summary of the pros and cons of Evaporative vests, paraffin vests and the StaCool Under Vest.

Evaporative Vest


  • Relatively inexpensive
  • Good for dry climates


  • Leaks water on clothes
  • Not effective in humid environments
  • Feels heavy and soggy
  • Cannot be worn under clothes
  • Looks industrial – not stylish

Paraffin Vest


  • More effective cooling than and evaporative vest
  • Provides dry cooling
  • Does not require a freezer to prepare for use. Cold water or a refrigerator is adequate.


  • Less effective than ice or other chemical pack cooling vests
  • Relatively short cooling times
  • Solid paraffin blocks can be uncomfortable
  • Flammable – limited application

StaCool UnderVest


  • Long cooling times – up to 3 hours on one set of cooling ThermoPaks
  • Flexible vest and ThermoPaks allow great freedom of movement
  • Even cooling – no cold spots
  • Lightweight - 5.5 pounds
  • Slim vest can be worn and concealed underneath clothing
  • Non-toxic and non-flammable


  • Can be more expensive than other cooling vests
  • Cooling ThermoPaks must be placed in a freezer before use

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