The short answer: in a good thermocol box, 16mm dry ice pellets last 24–48 hours — even in Karachi’s heat. The long answer depends on how you store and handle it. Here’s everything we tell our own customers.
Why Dry Ice Disappears (Sublimation)
Dry ice doesn’t melt — it sublimates, turning straight from solid to CO2 gas at −78.5°C. Warm air speeds this up. Your job is simply to slow the warm air down.
5 Rules to Make Dry Ice Last Longer
- Use a high-density thermocol box — the single biggest factor. Our thermocol boxes →
- Keep it full — empty air space inside the box speeds sublimation. Fill gaps with newspaper or extra packing.
- Don’t open the box until you need to. Every opening dumps cold air.
- Keep the box in the shade, never in direct sunlight or a hot car cabin.
- Buy the right size — 5kg outlasts 2kg because there’s less surface area per kilo.
Safety Rules (Important)
- Never touch with bare hands — it causes cold burns. Use gloves or tongs.
- Never store in an airtight container — CO2 gas needs to escape; pressure can build up.
- Keep rooms ventilated — in a closed car or tiny room, CO2 can displace oxygen.
- Keep away from children and pets.
Frequently Asked Questions
Can I keep dry ice in a freezer?
A regular freezer (−18°C) is warmer than dry ice (−78.5°C), so the dry ice still sublimates — but a freezer slows it down versus room temperature.
How much dry ice do I need for 24 hours?
For a standard thermocol box in Karachi weather, 3–5kg of 16mm pellets is a safe bet. Order dry ice →
Questions? Call 0310-2395910 or WhatsApp us.