Click here for a comprehensive answer, with tables showing safe temperature ranges across seasons and animal types. 

RedlineShipping.com offers 40- and 72-hour heat packs. 40-hour heat packs are most often used for reptile shipping. Reptiles must be shipped Priority Overnight or Standard Overnight, and the 40-hour heat pack is appropriate. Heat packs of less than 40 hour duration do NOT meet our Shipping Standards.

Do not use the 12- or 24-hour packs available at your local BigBox store or ski shop. Those packs are hand warmers, not shipping tools. The 12-24 hour packs don’t provide the necessary heat nor duration for a successful live shipment. 12 and 24 hour hand warmers also peak at a much higher temperature than shipping heat packs (peaking at 180F) endangering the life of your live shipment. 

Heat packs work through a chemical reaction between the contents of the heat pack and oxygen in the surrounding air. Oxygen flow is regulated through the perforated red line. Never cover the red line with tape or anything else.

Pre-start your heat pack an hour before shipping. Remove it from the outer wrapper, shake it up well, and place it in a folded towel, allowing it to warm up to a strong, solid heat. The heat pack will not heat up properly if you leave it in the open air.

The heat pack must be well started before you tape it (do not rely on the adhesive back) to the underside of the top insulation panel and seal your box. Remember not to tape over the perforated red line. The red line should face the interior of the box.

Note: Do not overuse heat packs! Use only one heat pack per box unless you are using our largest box, the 30"x16"x10", where two heat packs can be used if needed. Two heat packs in a box 16x16x8 or smaller will cause the box to get too hot and can kill the animal. Using two heat packs in a box smaller than 30"x16"x10" will also invalidate Live Arrival Insurance.

We have seen shipments where folks have put multiple heat packs in a box, thinking "if one is good, two is better!" or “reptiles like it hot!”. This has resulted in the loss of the animals.

In a small or medium sized box, multiple heat packs will raise the ambient temp of the box to very dangerous territory. Check the chart below for the temps that a single heat pack puts out. More is absolutely not better, just much, much hotter. Hand warmers in particular peak at 180F!

The purpose of a heat pack is NOT to warm or heat the box, it is to prevent it from getting cold. You want a temperate box, NOT a hot box!

If the temperatures are near the lower end of the Redline Shipping guidelines then doubling the insulation and/or having the shipment held at a FedEx facility will minimize the chances for a DOA.

DOAs are often caused by improper use of heat packs during the winter. Using too many heat packs in a box can cause the inside of the box to overheat. Following these guidelines will increase your chances of having successful shipments.

8 Critical Points for Heat Pack Use

• Activate the heat pack at least an hour before use. Remove outer wrapper, shake vigorously, then wrap in a towel to allow proper heating.
• Heat packs should never come into direct contact with the animal bag/container. 
• There should always be crumpled newspaper or other packaging material between the heat pack and animal bag/container.
• Heat packs require oxygen to work. Airholes (two ¼” holes at each end of the box, four total) are critical to allow enough oxygen to reach both the pack and the animal.
• The heat pack should never be placed under an animal bag/container, as it will likely result in a DOA.
• The heat pack should be taped securely (do not rely on the adhesive back) to the underside of the insulated foam lid. DO NOT cover the red stripe with tape! 
• Failure to comply with the above points will INVALIDATE Live Arrival Insurance.
• Lastly, we do not recommend heat pack use in any box smaller than the 12x9x6. If you need a heat pack with your shipment, you should use the 12x9x6 box or larger. 

Note: New heat packs are soft and feel like loose powder. Used heat packs are hard. If your heat pack is hard, it has been compromised. Use a different one.

WARNING: The following non-compliance of heat-pack usage will INVALIDATE any Live Arrival Insurance purchased:

• Using hand-warmers, foot-warmers, or any heat pack with a less-than 40 hour duration.
• Using more than one heat pack in any box smaller than 30"x16"x10". The 30"x16"x10" box may include up to TWO heat packs.
• Failure to provide specific ventilation (four quarter-inch holes, two at each end of the box).
• Placing the heat pack at the bottom of the shipping box and/or in direct contact with the animal or the container the animal is in.
• Attaching the heat pack facing the wrong way or covering the red stripe with tape.

Soak in water for a minimum of 15 minutes, until fully saturated.

Put the cold pack in your freezer, plastic side down, overnight. It should be fully frozen.

Pack your animal, but don’t place the cold pack until you’re ready for pickup or dropoff. This keeps the cold pack frozen longer.

When you’re ready to seal the package, wrap the cold pack in newspaper to absorb condensation. Tape the pack to the underside of the top insulation panel. Make sure there is packing material (usually crumpled newspaper) between the cold pack and the deli cup or cloth reptile bag.

Note: Dry Ice is NOT ALLOWED in any Redline Shipping package. It is strictly prohibited.

Directions for Use:

Cooling Supplement: Refrigerate the Ship-Safe Phase Pack to pre-cool to the desired temperature. For best results, the temperature should be below the phase change temperature of 74° F.

Heating Supplement: Pre-warm the Ship-Safe Phase Pack in a warm water bath to the desired temperature. For best results, the temperature should be above the phase change temperature of 74° F.

DO NOT MICROWAVE

Ship-Safe Phase Packs are Eco-friendly reusable phase change shipping packs

• Multiple packs may be safely used as Ship-Safe Phase Packs don't generate their own heat
• Ship-Safe Phase Packs may be used in conjunction with heat packs or cold packs to extend effective heating/cooling window
• A popular heat pack substitute for amphibians, and species such as crested geckos, that are sensitive to temperature spikes that come with shipping heat packs
• Ship-Safe Phase Packs are eco-friendly and reusable 
• Contents are natural, biodegradable and compostable