Insulated bag: 2, 4 or 6 layers?
Two, four or six layers: the difference may seem small, but it determines how many hours you can bridge. Here's how to choose without guessing.
What a layer does
Each layer consists of bubble wrap with a metallised outer surface. The metallic layer reflects radiant heat, while the air bubbles in the bubble wrap slow down heat transfer. More layers means more trapped air, and therefore slower warming.
Two layers
The lightest version. Suitable for same-day deliveries and next-day shipments where the package isn't outside for long. The advantage is weight and volume: you don't pay postage for insulation you don't need.
Four layers
The standard choice for chilled transport within 24 hours. This is the version most shippers use for meat, fish, dairy and meal boxes.
Six layers
For frozen goods, long transit times and warm months. With frozen products the margin is small: the product must stay frozen, not just cool. In that case, the extra delay from six layers is the difference between arriving intact and failing.
Calculate for your longest route
Not the average. A shipment that normally arrives within the day can, in case of delay, be left standing overnight. Choose the version that can still handle that scenario.
Layers don't replace cooling
A bag doesn't cool, it slows down warming. Buying more layers while sending too little coolant along solves nothing. Choose the right amount of ice packs first, then the number of layers.
Not sure?
Go one size up in layers in hot weather, for parcel transport with transshipment, and for products where you don't want to take any risk. The price difference per shipment is small compared to a rejected shipment.
