Fibre-Based Insulated Liners vs EPS: Hold Time and Cost per Hour in Co
Fibre-Based Insulated Liners vs EPS: Hold Time and Cost per Hour in Cold-Chain Delivery
For the 24–72 hour refrigerated lanes that most subscription meal-kit and DTC food deliveries run on, fibre-based insulated liners and molded EPS foam land in the same hold-time bands: roughly 24–48 hours with a 25 mm (1 in) wall and 48–72 hours at 38 mm (1.5 in), provided the liner fits the carton…
Summary
For the 24–72 hour refrigerated lanes that most subscription meal-kit and DTC food deliveries run on, fibre-based insulated liners and molded EPS foam land in the same hold-time bands: roughly 24–48 hours with a 25 mm (1 in) wall and 48–72 hours at 38 mm (1.5 in), provided the liner fits the carton without gaps. EPS keeps the lead past 72 hours and on frozen loads. EPS often wins the per-piece quote, but once dimensional freight, warehouse space, and end-of-life disposal are priced in, the fibre system usually works out cheaper per hour of hold on refrigerated lanes. The defensible number comes from your own pack-out math: total recurring cost — liner, gel packs, outer box, freight, labor, disposal — divided by tested hold hours, re-run for summer and winter.
Estimated reading time: 4 minutes
Two variables set hold time before material choice does
Every cold-chain pack-out is sized by two inputs: how long the box is in transit, and which temperature band the product must hold. Answer those first, because they determine the insulation class and the refrigerant load before price enters the conversation. Industry specification guidance is consistent about the bands: reflective radiant barriers suit shipments under 24 hours; 25 mm (1 in) of foam or fiber covers roughly 24–48 hours; 38 mm (1.5 in) extends refrigerated holds toward 48–72 hours; beyond that, and for frozen goods, buyers move to thicker or higher-performance constructions.
Ambient conditions move the goalposts. The harsher the weather on the lane, the more insulation it takes before the inside of the box drifts toward equilibrium with the outside — which is why a pack-out that survives a January route can fail the same route in July.
Where fibre and EPS genuinely differ on hold time
At equal thickness, fibre panels and foam occupy the same specification tiers for refrigerated goods. The insulation value of a paper-based liner comes from countless microscopic air pockets locked into the panel structure, which slow heat transfer much the way foam's closed cells do. For refrigerated meal-kit payloads inside the 24–72 hour window, hold time alone rarely decides the comparison.
Molded EPS retains an advantage at the extremes. Past roughly 72 hours, and whenever the payload must stay frozen for two days or more, rigid foam is still the safer default at common wall thicknesses. The variable that quietly decides real-world performance with either material is fit: even small gaps short-circuit the wall, bleeding cold the way a propped-open cooler door bleeds a kitchen, so a fibre liner cut to your exact carton will outperform a nominally superior material fitted badly.
The per-piece quote is not the cost
On a unit-price comparison, molded EPS coolers frequently look cheapest, and for the bare molding they often are. The system cost tells a different story. EPS ships and sits in the warehouse as finished volume, so you pay freight and rack space for air; fibre liners ship flat or compressed and are erected at the pack-out bench, which trims inbound cube and storage footprint on every replenishment cycle.
Disposal lands on your customer, and it feeds back into your economics. Many municipal curbside programs do not accept EPS, while paper-based insulation can ride the household paper stream — which is why DTC brands increasingly treat the disposal stream as part of the packaging decision rather than an afterthought.
Adding gel packs: the cost-per-hour formula
Gel packs, not the liner, are usually the largest recurring line in a refrigerated pack-out. A common starting ratio is about 1 lb (0.45 kg) of gel for every 5 lb (2.3 kg) of refrigerated payload, tuned from there by test. That weighting is exactly why the honest comparison between liner systems is cost per hour of verified hold:
Run that formula per lane and per season. If Liner A costs slightly more per unit but reaches 48 hours with one fewer gel pack, or avoids a dimensional-weight surcharge by shipping flat, its cost per hour can beat the nominally cheaper EPS cooler. Temperature loggers or a chamber test turn the ratio from a guess into a number, and a documented summer and winter pack-out keeps the result valid when the weather shifts.
When EPS still wins, and when fibre clearly does
Choose molded EPS or another rigid foam when a load must stay frozen beyond 72 hours, when lanes run through extreme ambient heat, or when your operation already runs a reusable closed loop built around rigid coolers. Those conditions are real, and pretending one material fits every lane is how cold-chain budgets leak.
Fibre wins the widespread case: refrigerated shipments inside the 24–72 hour window, freight cube and storage space under pressure, destination markets that expect curbside-recyclable packaging, and unboxing moments that are part of the brand. Many DTC operators land on both — fibre for the standard refrigerated menu, a smaller EPS footprint for the frozen subset.
Sourcing the fibre side of a cold-chain pack-out
Switching to fibre insulation reopens decisions that surround the liner: the outer box, moisture-resistant coatings, carton fit, and print. That surrounding fibre layer is where TakeawayPack works — a foodservice-packaging sourcing partner operating a self-owned printing plant alongside a network of packaging factories, serving buyers across North America, Europe, Australia, the Middle East, and Japan/Korea with boxes, containers, trays, and printed components.
A request can specify product category, material, size or capacity, estimated quantity, printing customization, and destination port or country; at the inquiry stage you can discuss structure, coatings, capacity, printing, lid matching, and carton packing, and production starts only after a digital proof is approved in writing. Compliance claims are handled the same disciplined way: food-contact, FSC or GRS documentation, origin, and compostability are confirmed per SKU and destination market rather than assumed from a catalog, because certification attaches to the product you buy, not to a supplier's catalog. Select kraft and molded-pulp lines carry compostable or recyclable certification in that same SKU-by-SKU sense — ask for the documentation that matches the exact item you plan to order, via the certifications and materials page.
Quick answers
Do fibre insulated liners hold temperature as long as EPS?
For refrigerated shipments in the 24–72 hour range, yes at equal wall thickness — both materials sit in the same specification tiers. Beyond 72 hours, and for frozen payloads, rigid foam keeps the edge at common thicknesses.
How do I calculate which liner is cheaper per hour of hold?
Add every recurring pack-out cost — liner, gel packs, outer box, allocated freight and storage, labor, disposal — and divide by hold hours verified in a test, not claimed on a datasheet. Compare lane by lane and season by season.
How many gel packs should a meal-kit box carry?
Start near 1 lb (0.45 kg) of gel per 5 lb (2.3 kg) of refrigerated payload, then adjust with logger or chamber testing. Pre-chill the product, place gel packs top and bottom, and eliminate air gaps so the refrigerant cools the food rather than the void.
When does EPS remain the better buy?
Frozen menus past 72 hours, extreme-heat lanes, and reusable closed-loop programs remain natural EPS territory. For standard refrigerated meal-kit lanes, run the cost-per-hour formula first — fibre frequently wins it.
For a packaging request built around your menu, lanes, and destination market, visit Takeawaypack.
