If you’re sending perishable goods, medications or meal kits for forty eight hours, one question quickly surfaces: is dry ice better than gel packs for two day shipping? The answer depends on how cold your product must stay, how long it will be in transit and how much risk you can accept. Dry ice stays at –78.5 °C and can freeze items for days, whereas gel packs keep goods between 0 °C and 10 °C for hours to a couple of days. Choosing the wrong coolant can damage your product, inflate costs and even violate regulations. This guide uses current evidence and 2025 insights to help you make the right call.
Cooling requirements: Understand how product type, temperature range and transit time dictate whether dry ice or gel packs are better for two day shipping.
Pros and cons: Compare dry ice and gel packs in terms of duration, safety, cost, handling and sustainability using real data.
Packing methods and calculations: Learn how much dry ice or gel packs you need for a 48 hour shipment and how to pack for maximum efficiency.
Latest trends: Explore 2025 innovations such as phase change materials (PCM), sustainable gel packs and smart monitoring that may outperform traditional methods.
FAQ and practical tips: Find answers to common questions about two day cold shipping and actionable advice for safe handling, regulatory compliance and customer satisfaction.
What Determines Whether Dry Ice or Gel Packs Are Better for Two Day Shipping?
Quick answer: The right choice depends on the product’s temperature tolerance and how long you need to maintain it. Dry ice reaches –78.5 °C (–109.3 °F) and keeps items frozen for multiple days, whereas gel packs maintain a chilled range between about 0 °C and 10 °C. Products that must remain frozen—like ice cream, meat or certain pharmaceuticals—benefit from dry ice, while those that require refrigeration but cannot freeze—such as fresh produce, dairy or temperature sensitive medicines—fare better with gel packs. Two day shipping sits at a tipping point: long enough that standard ice may fail but short enough that careful packaging with gel packs can suffice in mild climates..
Why Temperature Range Matters
Dry ice is frozen carbon dioxide. Its surface temperature of –109.3 °F (–78.5 °C) makes it far colder than water ice and requires considerable heat to sublimate—more energy than it takes to melt gel packs. This high latent heat explains why dry ice keeps goods frozen for a long time. However, it also means dry ice can freeze and damage items sensitive to low temperatures, such as fresh flowers, soft cheeses or certain vaccines. In contrast, gel packs are filled with water or polymer gel and maintain 2–8 °C, the typical refrigeration range for pharmaceuticals and perishable foods. Gel packs will not drop temperatures below freezing, making them safer for items that must stay cold but not frozen.
Duration and Heat Load
When shipping for two days, you need a coolant that can handle the heat load throughout the entire journey. Dry ice sublimates gradually, losing about 5–10 lb per 24 hours in a well insulated box. Guidelines from Insulated Products Corporation recommend using dry ice equal to the weight of the payload for 48 hour shipments. Gel packs provide cooling for shorter periods; typical gel packs weighing 1.5–2 lb can last up to three days, but their cooling capacity diminishes as they thaw. Businesses often follow the rule of one pound of gel per cubic foot of space per day, meaning two days would require two pounds per cubic foot. Because gel packs absorb heat as they thaw, combining them with insulation is crucial to extend performance.
Safety and Handling Considerations
Handling differences are a major factor in choosing between dry ice and gel packs. Dry ice demands protective gloves and proper ventilation; touching it can cause frostbite, and sublimated carbon dioxide can displace oxygen in enclosed spaces. Shipping dry ice is regulated: packages over 5.5 lb must meet U.S. Department of Transportation and International Air Transport Association (IATA) rules. Airlines typically limit passengers to 2.5 kg (about 5.5 lb) of dry ice per shipment. Gel packs, however, are non toxic and require no special handling. They are safer for food contact, easier to dispose of and not subject to hazardous materials regulations.
Cost and Environmental Impact
Cost often drives the decision. Dry ice is more expensive upfront and perishable; you cannot refreeze or reuse it once it sublimates. It may be cost effective for extended shipments because a single block can last longer than multiple gel packs. Conversely, gel packs are cheaper and reusable, making them economical for frequent shipments. Environmental considerations also differ: gel packs are often recyclable and create minimal waste, whereas dry ice dissipates into CO₂ gas but has a carbon footprint from production and transport. Sustainable innovations like biodegradable gel packs and renewable energy dry ice production can mitigate these impacts.
Table 1 – Dry Ice vs. Gel Packs for Two Day Shipping
| Feature | Dry Ice | Gel Packs | Practical Significance |
| Temperature range | Extremely cold at –78.5 °C (–109.3 °F) | Chilled at approximately 0–10 °C | Determines if product freezes or stays refrigerated |
| Duration (48 h) | Lasts multiple days; plan on equal weight to payload for two days | Typical gel packs (1.5–2 lb) last up to three days; require more packs | Influences how many coolant units are needed |
| Handling & safety | Requires insulated gloves, ventilation, special labelling | Non toxic and easy to handle | Affects staff training and compliance costs |
| Regulatory requirements | Classified as a hazardous material; shipments >5.5 lb must meet IATA/49 CFR rules | No hazardous classification | Impacts paperwork and permitted quantities |
| Cost & reusability | Higher upfront cost; single use (sublimates) | Lower cost; reusable and recyclable | Determines long term shipping budget |
| Best for | Frozen foods (ice cream, seafood), long journeys | Chilled goods (produce, dairy), temperature sensitive pharmaceuticals | Guides appropriate product pairing |
User Friendly Tips and Recommendations
For frozen goods: If shipping frozen meat, ice cream or laboratory samples for two days, dry ice is usually the superior choice. Use a well insulated box and plan dry ice equal to the weight of your product for 48 hours. Place the dry ice on top of the package so cold air sinks over the goods and vent the container to allow CO₂ to escape.
For refrigerated goods: If your shipment must stay between 2 °C and 8 °C (e.g., cheese, chocolates or vaccines), choose gel packs. Follow the rule of one pound of gel per cubic foot per day and ensure the product does not touch the packs directly to avoid cold spots.
For mixed loads: When shipping items that need refrigeration but may benefit from longer duration or higher thermal mass, combine gel packs with a small amount of dry ice or PCM. For example, layering a +5 °C PCM brick around insulin and placing dry ice outside the insulation prevents freezing while maintaining a stable cold zone.
Trial runs: Before sending high value items, perform a trial shipment with a temperature logger to confirm that your chosen method maintains the required temperature for 48 hours.
Real world case: A biotech company needed to ship 2 lb of cryopreserved cell samples across the country during summer. The transit time was 36–48 hours. Following the dry ice guidelines, the shipper used an insulated container and 2 lb of dry ice—equal to the sample weight—for the first 24 hours and an additional 1 lb to accommodate higher ambient temperatures. A temperature logger showed that the internal temperature stayed below –20 °C for 44 hours, confirming the appropriateness of dry ice for two day frozen shipments.
How to Choose the Right Cooling Method for Your 48 Hour Shipment
Selecting a cooling method is not one size fits all. The following framework will help you decide whether dry ice or gel packs are better for your two day shipping needs.
Identify the acceptable temperature range. Ask whether the product must stay frozen (< 0 °C), chilled (2–8 °C) or ambient (15–25 °C). For goods that must remain below freezing, dry ice is the only viable option because gel packs cannot reach such temperatures. For chilled goods that should not freeze—like certain pharmaceuticals, dairy or delicate produce—use gel packs.
Assess product sensitivity and packaging. Determine how susceptible your product is to freezing damage or temperature fluctuations. Live seafood, flowers and some biologics can be harmed by sub zero temperatures. Packaging such as rigid containers and bubble wrap can help buffer the product against direct contact with cold sources. Combining a +5 °C PCM layer between the product and dry ice can prevent freezing while benefiting from the long duration of dry ice.
Calculate the required coolant weight. For dry ice, guidelines recommend half the product weight for overnight shipments, equal weight for 48 hour shipments and 1.5× weight for 72 hours. For gel packs, use one pound per cubic foot per day and consider that typical 1.5–2 lb gel packs last three days. If your package will encounter extreme heat (ambient > 32 °C/90 °F), plan to increase dry ice by 8–15 lb for each extra day.
Check transportation regulations. If shipping by air or crossing borders, ensure your dry ice quantity does not exceed the carrier’s limit (often 5.5 lb or 2.5 kg). Label packages with UN 1845 for dry ice and include net weight. Gel packs typically avoid these restrictions.
Evaluate cost and sustainability. For high volume shipments, the reusability of gel packs may offer lower long term cost despite needing multiple units. Dry ice may be cost effective for occasional long distance shipments or when the product value outweighs the coolant cost. Consider environmentally friendly gel packs or PCM that reduce waste.
Dry Ice vs. Gel Packs for Pharmaceuticals and Food Shipments
Pharmaceuticals often require a narrow temperature range to maintain efficacy. Vaccines and biologics typically need 2–8 °C; using dry ice would freeze and potentially degrade them. In this case, gel packs—or PCM bricks rated for +5 °C—are ideal. For insulin, guidelines suggest storing it between 2–8 °C and never freezing it. When shipping insulin for more than a day, buffer it with +5 °C PCM inside a rigid case and surround the case with insulation and dry ice; this layering prevents freezing and extends the cold zone.
For food shipments, classification depends on whether the item must stay frozen or simply chilled. Frozen meats, seafood and ice cream require dry ice to remain solid during transit. Fresh produce, cheese and chocolates are sensitive to freezing and maintain quality best with gel packs. Always separate food from direct contact with dry ice or gel by using plastic liners or trays.
Table 2 – Recommended Coolant Amounts for 48 Hour Shipping
| Payload Weight | Dry Ice Required (48 h)* | Gel Pack Required (48 h)† | Meaning |
| 1 lb (0.45 kg) | 1 lb dry ice | ~2 lb gel packs (two 1 lb packs) | Enough cooling for small sample kits |
| 2 lb (0.9 kg) | 2 lb dry ice | ~4 lb gel packs | Supports medium meal kit shipments |
| 5 lb (2.3 kg) | 5 lb dry ice | ~10 lb gel packs | Required for small frozen food boxes |
| 10 lb (4.5 kg) | 10 lb dry ice | ~20 lb gel packs | Suitable for large shipments or groups |
| 20 lb (9 kg) | 20 lb dry ice (or 1.5× for hot climate) | ~40 lb gel packs | For full coolers or large seafood orders |
| *IPC guidelines suggest using dry ice equal to payload weight for 48 hour transit and adding 8–15 lb more per additional day in very hot conditions. | |||
| †Gel pack weight is calculated as one pound of gel per cubic foot per day; weight increases with container volume and ambient temperature. |
Tips for Specific Scenarios
Shipping meal kits: Meal kit services often include both refrigerated ingredients (vegetables, dairy) and frozen proteins. Use gel packs for ingredients that need to stay around 4 °C and dry ice or PCM for proteins that must remain frozen. Place a cardboard divider between sections and pack dry ice above the frozen compartment so cold air circulates downward.
Global shipping: For cross border shipments longer than two days, consider dry ice plus PCM and choose carriers that allow dry ice. Validate compliance with IATA and local regulations. Alternatively, use ultra low PCM packs (e.g., –20 °C) that may avoid dry ice regulations but still deliver sub zero temperatures.
Hot climates: When ambient temperatures exceed 32 °C, increase your dry ice by 30–50 % or add reflective insulation. Gel packs alone may not survive extreme heat. Fill empty space with crumpled paper or air pillows to reduce heat gain and sublimation.
Return logistics: For subscription services, supply prepaid return labels for gel packs so customers can send them back for reuse. This reduces waste and supports sustainability goals.
Actual application: A chocolate company shipping handcrafted truffles in July used a combination of gel packs and reflective insulation. The truffles needed to remain between 10 °C and 20 °C to preserve texture and flavor. They used 4 lb of gel packs (two packs on each side) and a foam liner. A temperature logger showed the interior stayed between 7 °C and 12 °C for 52 hours, demonstrating that gel packs, when paired with proper insulation, suffice for two day summer shipments of sensitive chocolates.
Packing Best Practices for Two Day Cold Shipping
Proper packing is as important as choosing the right coolant. A well designed pack out minimises heat gain, maximises cooling duration and ensures safety.
Choose the right container. Use an insulated cooler or box with at least 2 inches of foam or urethane insulation. Expanded polystyrene (EPS), expanded polypropylene (EPP) and polyurethane foam are common. A 2 inch urethane insulated box will cause 5 lb of dry ice to sublimate every 24 hours.
Pre cool the coolant. Freeze gel packs or PCM bricks fully before packing. Store dry ice in a well ventilated freezer or cooler to slow sublimation.
Use rigid product containers. Place your product in a rigid, watertight container or secondary box to protect it from direct contact with coolant and potential moisture. For pharmaceuticals, vials and insulin pens should be sealed in protective cases.
Layer the coolant. For dry ice, place blocks on top of the product to allow cold CO₂ gas to fall and envelop the contents. Surround the sides with smaller pieces or pellets to fill gaps. For gel packs, distribute them evenly around the product, leaving air space for circulation and avoiding direct contact. For mixed shipments, insert a PCM barrier layer between gel packs and product to avoid freeze damage.
Fill empty space. Use crumpled paper, foam peanuts or air pillows to reduce convection inside the box. Less empty space means slower heat transfer and slower sublimation.
Ventilate for dry ice. Puncture a small hole or loosen the lid slightly to allow CO₂ gas to escape; never seal a dry ice package completely. Mark the package with “Dry Ice (UN 1845)” and the net weight for regulatory compliance.
Label and track. Clearly label the package with “Perishable” or “Keep Refrigerated/Frozen.” Use a temperature data logger or time temperature indicator to monitor performance. This data can validate your process and support regulatory documentation.
How Much Dry Ice or Gel Packs Do You Need?
Calculating the right amount of coolant ensures your product remains in the safe temperature zone for 48 hours without wasting resources.
Dry ice: According to Insulated Products Corporation, for overnight shipments use dry ice equal to half the product weight; for 48 hour shipments use equal weight; and for 72 hour shipments use 1.5× weight. Cardinal Health adds that you may need 8–15 lb of extra dry ice per additional day under high heat. A 2 lb payload shipping for two days would need roughly 2 lb of dry ice, but if the ambient temperature is above 32 °C (90 °F) or the container insulation is thin, increase to 3–4 lb.
Gel packs: Follow the one pound per cubic foot per day rule. For a box measuring 12 × 10 × 8 inches (0.56 cubic feet), you would need roughly 1 lb of gel per day or 2 lb for two days. Because gel packs come in 1.5–2 lb sizes, two packs may suffice. However, if shipping in extreme heat or using a larger container, consider adding another pack or using a PCM brick for additional thermal mass.
Combination strategy: For sensitive items like insulin or biologics, layering a +5 °C PCM between the product and dry ice ensures safe refrigeration without freezing. You might use two PCM bricks (approx. 0.5 lb each) surrounding the product, with 3 lb of dry ice around them for a two day shipment. This strategy maintains 2–8 °C inside the product cavity while benefiting from the longevity of dry ice.
Case in point: A seafood exporter shipping 5 lb of live lobster cross country used 5 lb of dry ice based on the equal weight guideline. However, the shipment was scheduled during a heatwave (ambient 35 °C). They added an extra 3 lb of dry ice and lined the cooler with reflective insulation. Temperature logs showed the internal temperature stayed below –10 °C for 40 hours and below 0 °C for 50 hours, confirming that adjusting for heat load is critical.
2025 Trends and Innovations in Two Day Cold Shipping
The cold chain industry continues to evolve. Several innovations are shaping how businesses approach two day shipping and beyond:
Latest Developments
Phase change materials (PCM) with custom melting points: PCM gel packs that freeze at +5 °C, –20 °C or even –65 °C are increasingly available. They offer targeted temperature zones without the hazard of dry ice and can be reused many times. A 2024 study found that PCM bricks maintain 2–8 °C for over 48 hours in insulated shippers, outperforming standard gel packs in high heat environments.
Smart packaging and IoT monitoring: Temperature loggers and Bluetooth sensors integrated into shipping boxes allow shippers to monitor conditions in real time. Alerts can notify carriers of temperature excursions, enabling corrective action during transit.
Sustainable materials: Manufacturers are producing biodegradable gel packs made from plant based materials and recyclable wrappers. Dry ice production is shifting toward using renewable CO₂ sources captured from industrial processes, reducing greenhouse gas emissions.
Modular insulation systems: Pre validated shipping kits that combine vacuum insulated panels with PCM provide consistent performance for 48–72 hour shipments without dry ice. These systems reduce weight and meet strict pharmaceutical regulations.
Hybrid coolants: Some innovators are blending small quantities of dry ice with PCM or gel packs to achieve extended durations while minimising hazards. Automated dosing algorithms calculate the optimal blend based on product weight, destination climate and transit time.
Market Insights
Demand for two day shipping of temperature sensitive products has surged due to e commerce meal kits, direct to consumer pharmacies and telehealth services. Customers expect fresh, safe deliveries, and regulatory scrutiny has intensified. In 2025, the global cold chain packaging market is forecast to exceed $80 billion, with a compound annual growth rate above 15%. Businesses adopting smart, sustainable and compliant cooling strategies will gain a competitive edge.
Frequently Asked Questions
Q1: Can I use both dry ice and gel packs together for two day shipping?
Yes. Combining gel packs or PCM with dry ice helps maintain a safe temperature range and prevents freezing. Place a PCM barrier around the product, then surround with dry ice for long journeys. This hybrid approach is ideal for delicate pharmaceuticals and mixed food shipments.
Q2: How do I dispose of dry ice after my package arrives?
Allow dry ice to sublimate in a well ventilated area away from pets and children. Never place it in a sealed container, sink, toilet or trash can, as gas buildup can cause pressure hazards. Gel packs can be reused or drained according to the manufacturer’s instructions.
Q3: Are there any products that should never be shipped with dry ice?
Yes. Products sensitive to freezing—such as certain vaccines, fresh produce, flowers and live seafood—should not be exposed to dry ice. Use gel packs or PCM that maintain above freezing temperatures instead.
Q4: What if my shipment exceeds airline dry ice limits?
Airlines often restrict passengers to 2.5 kg (5.5 lb) of dry ice. For larger shipments, choose ground or air cargo services that allow higher amounts. Alternatively, use PCM gel packs with a lower melting point, which avoid dry ice classification.
Q5: How do I calculate the size of insulated container needed?
Measure the product dimensions and add space for coolant and insulation. The box should allow at least 2 inches of insulation on all sides. Larger boxes require more coolant because empty space increases heat gain. Follow the one pound of gel per cubic foot per day rule or equal weight dry ice guideline to scale coolant accordingly.
Summary and Recommendations
Two day shipping requires a careful balance between temperature control, cost, safety and regulatory compliance. Dry ice delivers ultra low temperatures and extended cooling durations, making it the best choice for frozen goods like seafood or ice cream. However, it demands protective handling, compliance with hazardous materials regulations and sufficient ventilation. Gel packs provide reliable refrigeration within 0–10 °C and are safer and reusable, ideal for perishable foods and pharmaceuticals. For two day shipping, plan dry ice equal to the product weight or one pound of gel per cubic foot per day and adjust for ambient temperature.
Final Advice:
Identify the necessary temperature range and product sensitivity to choose the appropriate coolant.
Calculate the required weight of dry ice or gel packs based on payload weight, container size and ambient conditions.
Use proper packaging: insulated boxes, rigid product containers, coolant layering and ventilation.
Follow regulations for dry ice shipments and label packages clearly.
Consider new technologies such as PCM gel packs and smart monitoring to enhance performance and sustainability.
By following these steps, you can ensure your products arrive safely, maintain quality and delight your customers every time.
About Tempk
Tempk is a leader in cold chain solutions, providing pre validated packaging, PCM gel packs and expertise for shipping pharmaceuticals, food and biotech products. We specialise in designing hybrid cooling systems that maintain 2–8 °C for over 72 hours, ensuring your shipments meet strict regulatory requirements. Our reusable PCM bricks reduce dry ice consumption and support sustainability goals. With a focus on safety, compliance and innovation, we help businesses deliver temperature sensitive goods with confidence.
Call to Action: Ready to optimise your two day shipments? Contact Tempk’s cold chain experts today for tailored recommendations and pre validated packaging solutions that protect your products and your brand.
