At 30 hours, gel wins. At 72 hours, dry ice usually wins. Somewhere between the two there is a crossover, and most exporters guess it at 48 hours when the real number for their lane is 61. Getting that wrong costs either $0.80 a box or a rejected consignment, depending on which way you miss.
The crossover is not a property of the refrigerants. It is a property of your lane length, your fill cost, your dangerous goods handling fee and — the part everyone forgets — the amount of overfill you buy to cover delay.
Two very different cost shapes
Filled gel runs $0.55 to $0.85 per kilo at the packing line, holds roughly 430 kJ per kilo across its usable band, and can be reused on a returnable programme. Dry ice runs $1.05 to $1.30 per kilo ex plant, sublimates at 1.5-2 percent per hour in a good shipper, and holds 571 kJ per kilo of latent heat at -78.5 °C — a much colder sink, which is the reason it dominates for frozen lanes rather than chilled ones.
Sublimation is what kills the short-lane case for dry ice. A 10 kg block on a 30-hour routing will be down to about 5.5 kg on arrival, which means you bought 10 kg to deliver 5.5 kg of cooling. On a 30-hour lane, gel delivers roughly 92 percent of what you paid for.
The fees that move the crossover
Dry ice travels as dangerous goods. That brings a shipper’s declaration, a trained signatory, vents in the box, quantity limits per compartment, and a ground handling charge that runs $25 to $60 per shipment at many stations, sometimes more for small consignments. Add the cost of the extra box volume for the vents and the label stock, and a lane that looks 15 percent cheaper on refrigerant cost can be 40 percent more expensive per shipment.
| Lane length | Gel per box | Dry ice per box | Verdict |
|---|---|---|---|
| 24 h | $5.60 | $13.00 plus DG fee | Gel, clearly |
| 48 h | $9.80 | $16.40 plus DG fee | Gel unless volume is tight |
| 72 h | $15.40 | $19.80 plus DG fee | Close, decided by handling |
| 96 h | $23.10 | $22.60 plus DG fee | Dry ice on mass, gel on paperwork |
Read the last row carefully. Dry ice is cheaper on refrigerant at 96 hours, but it still carries the declaration, the trained signatory and the handling fee. Unless you ship that lane weekly and the fee amortises, gel is still the lower total.
The counter-intuitive case: dry ice that spoiled a load
A salmon exporter switched a 40-hour chilled lane from gel to dry ice to save $2.10 a box. The product arrived at -2 °C on the surface and 4 °C at the core, with freeze damage along the belly wall where the bag had rested. Dry ice at -78 °C does not cool a chilled payload; it freezes a stripe of it. For any lane where the target is 0-4 °C, dry ice is the wrong tool regardless of cost, and no amount of baffling fully solves contact freezing.
Gel has the opposite hazard: it is too warm for frozen lanes. If you are moving product at -18 °C, a -18 °C pack has no gradient to work with, and you end up with a box that holds temperature only as long as the ambient stays below the product.
How to settle it for your lane
Cost the two options with overfill included, then add the handling fee for dry ice and the return freight for reusable gel. Run the number per kilo of product shipped rather than per box, because box fill rates vary and that is where comparisons usually go wrong. If the answer lands within 10 percent either way, choose gel — the paperwork is simpler and the failure mode is a warm box rather than a dangerous goods incident.
If gel wins on your numbers, size the mass against a real ambient profile rather than a nominal hold time. The logistics ice pack guide shows how to read a profile into a gel mass.
Da maohua
Zhengzhou Flor New Materials Co., Ltd. specializes in SAP super‑absorbent polymer products. Serving personal hygiene, agriculture & horticulture, pet supplies and other industries, we leverage supply‑chain resources to provide particle‑size selection, performance matching and customized solutions based on clients’ practical requirements.
