When it comes to keeping things cold, various solutions have evolved to cater to different needs. Among these, Phase Change Materials (PCMs), dry ice, and traditional ice packs are commonly used solutions. Each has its own set of characteristics, benefits, and drawbacks, making them the perfect or not-so-perfect solution depending on the need. In this blog, we’ll delve into the intricacies of these cooling methods and explore what sets them apart.

Phase Change Materials (PCMs)

Phase Change Materials (PCMs) are the least commonly used out of the three, but probably the most versatile. PCMs can store and release large amounts of energy allowing them to maintain a consistent temperature within a specific range for a long period of time. Depending on the environment and insulation, as well as the temperature of the payload, a PCM could maintain a consistent refrigerated, frozen, or ultra-cold temperature for multiple days. Because of its ability to be both customized by temperature and by size/weight, PCMs have a wide range of applications.

PCMs can be used for frozen food delivery, specimens, blood, vaccines, allografts, biologics transport, emergency disaster preparedness, or your everyday lunch box. Depending on the manufacturer, Thermal Custom Packaging being one of them, PCMs can be an entirely “green” product, as their plastic shells are made of HDHP plastic making them recyclable. Additionally, the PCM solution inside the hard plastic outer shell is non-toxic and environmentally friendly. Here are a few key characteristics that make them stand out: 


  • Precise Temperature Control: PCMs can be engineered to specific temperature ranges, ensuring that your goods stay within the desired temperature range throughout transport.
  • Reusability: PCMs can be reused multiple times, reducing waste and long-term costs.
  • Environmental Friendliness: PCMs are often considered eco-friendly, as they minimize waste and are non-toxic.


  • Initial Cost: PCMs may have a higher upfront cost compared to dry ice or traditional ice packs, but since they can be reused 1,000s of times, users of PCMs see huge cost-savings following their initial investment. 

Dry Ice

Dry ice, which is solid carbon dioxide (CO2), is an option for cold transport that offers extremely low temperatures. The use of dry ice in cold transport has revolutionized the way we preserve and transport temperature-sensitive goods. Its extreme cold makes it an indispensable tool for industries where temperature control is paramount, however, temperature customization and reliability are questionable. Here are some more unique considerations when using dry ice:


  • Extremely Cold: Dry ice can maintain temperatures as low as -78°C (-109°F), suitable for ultra-cold transport needs.
  • Sublimation: Dry ice sublimates directly from a solid to a gas, leaving no liquid residue and minimizing the risk of moisture damage to products.


  • Safety Hazards: Handling dry ice requires careful precautions, as it can cause frostbite or skin damage on contact. Packaging dry ice also brings with it some risk. If not properly packed and ventilated, dry ice could cause an explosion. 
  • Limited Duration: Dry ice has a limited lifespan, making it more suitable for shorter trips or as a temporary solution.
  • Cost: Up front costs for dry ice may be less expensive than PCMs, but more expensive in the long run. 

Traditional Ice Packs

A traditional ice pack is simply frozen water in a plastic pouch or shell. It has been widely used as a cooling solution to keep temperature-sensitive materials cold primarily due to its ease of use and accessibility. Depending on the insulation, these ice packs typically last about 12 hours or less. Although an ice pack is an easy, cost-effective, and safe refrigerant, it has its limitations, making it most useful for short transportation of temperature-sensitive contents, that only require refrigeration.  

Unfortunately, traditional ice packs eventually melt and when they do, they can create a wet and messy environment, potentially damaging sensitive items. Not all ice packs are created equal making them not very consistent or reliable depending on their environment. The cooling effect of ice packs can diminish quickly as the ice melts, leading to temperature fluctuations.

Also, like a PCM, once the ice pack melts, it does need to be refrozen, limiting its usability in situations where continuous cooling is required. Different from a PCM though, is the length of time a traditional ice pack can maintain its cold temperature, as it begins to melt as soon as it is out of a freezer.


  • Affordability: Traditional ice packs are readily available at low cost.
  • Simplicity: They are easy to use and require no special training.
  • Suitable for Short Trips: Traditional ice packs are suitable for relatively short transportation durations.


  • Limited Temperature Control: These packs can only maintain temperatures around the freezing point of water (0°C or 32°F).
  • Frequent Replenishment: Traditional ice packs need to be replaced or refrozen regularly for longer trips.
  • Environmental Impact: They generate plastic waste and have a higher environmental footprint due to their disposability.

In the realm of cooling solutions, each technology has its own unique characteristics, advantages, and limitations. 

The choice between phase change material, dry ice, and traditional ice packs for cold transport ultimately depends on the specific requirements of your shipment, your budget, and your environmental considerations.

  • PCMs offer precise temperature control and reusability, making them a sustainable choice for longer journeys with strict temperature requirements.
  • Traditional ice packs are affordable and suitable for short trips, but they lack temperature precision and generate plastic waste.
  • Dry ice is ideal for ultra-cold transport but requires careful handling and may not be suitable for longer durations.