Insulated shipping bags: types and sizes (English)
An insulated shipping bag is a flexible bag with reflective layers that you place inside a cardboard box, so chilled and frozen goods warm up more slowly in transit. You put the product in the bag, add a coolant such as gel packs, and close it. The bag does not create cold. It holds on to the cold your coolant gives off. Below you will find the types, the sizes and how to pack one.
Insulated shipping bags: three constructions
Our bags come in 2, 4 and 6 layers. They are made in our own production, in business since 1972, and ready from stock. The number of layers sets the insulation value. The same product is also called isolatiezak, koelzak, thermozak, thermal bag, insulated bag and cool bag shipping.
| Type | Construction | Best for |
|---|---|---|
| 2 layer | Insulating foam with a reflective outer film, fully white inside, self adhesive closing strip | Same day and next day shipments |
| 4 layer | Reflective metalized PET film with 8 mm bubble film | The efficient standard choice |
| 6 layer | Metalized PET, bubble film and extra insulating layers | Warm weather, longer transit and tightly controlled shipments |
For a side by side comparison in Dutch, see isolatiezak: 2, 4 of 6 laags.
Sizes of insulated shipping bags
The 2 layer bags come in six sizes: 25 x 35, 30 x 45, 35 x 35, 35 x 55, 67 x 52 and 70 x 70 cm. All six have a self adhesive closing strip. The 4 layer and 6 layer bags come in 25 x 35, 50 x 30, 70 x 40, 70 x 55, 70 x 70 and 110 x 70 cm, so the range runs from 25 x 35 to 110 x 70 cm.
- 25 x 35 cm: the smallest size, with the opening on the short side. Used for small shipments such as lab samples, cosmetics and small food items.
- 50 x 30 cm: the opening is on the long side, which suits wide products or several small packs placed side by side.
- 70 x 70 cm in 2 layer: a square bag that folds around standard crates and 600 x 400 mm boxes.
- 110 x 70 cm in 6 layer: the largest bag, for big orders or long products that do not fit smaller bags.
Looking to buy a specific size? Our Dutch guide isolatiebox voor verzending kiezen compares bags with other insulated packaging.
Insulated bag for shipping: how to pack it
Using an insulated bag for shipping is a matter of order and fill. Follow these steps:
- Place the products in the bag and fill it as tightly as you can. Less empty space means better cooling performance.
- Lay the gel packs on top of the products. Cold air sinks, so it cools evenly from the top down.
- Close the bag. The 2 layer bags have a self adhesive strip. Close other versions carefully with tape.
- Place the bag in a suitable cardboard box.
The number of gel packs depends on transit time, contents and outside temperature. We do not give a fixed number. If you are unsure, ask for advice or request a sample. Our Dutch article Ice pack verzenden: wat bepaalt het aantal? explains how to work it out.
Thermal bag for shipping: what goes inside
A thermal bag for shipping works best together with a coolant. Use ice packs or hard cooling elements if you prefer not to use gel packs. Typical uses are:
- meal kits and prepared meals;
- meat and fish, often sent by butchers and fishmongers with a webshop;
- dairy, vegetables and fruit, optionally with an absorbent mat against moisture;
- pharmaceutical and medical shipments, using the 6 layer bag for tightly controlled shipments. We do not promise compliance with any guideline.
Bag or EPS box?
For many chilled shipments, a bag inside your own cardboard box is a cheaper and more flexible alternative to an EPS box. It arrives flat, takes up much less storage space, is lighter and smaller in volume, and leaves no bulky, crumbly waste stream. The 6 layer bag is comparable in insulation to a thick walled EPS box. A paper version with an adhesive strip is also available for companies that want to be more sustainable. Read more in isolatiezak of EPS doos.
Choosing the right bag for your shipment
A 2 layer bag is the lightest and thinnest in the range and is enough for same day and next day shipments. If you face longer transit times or high outside temperatures, take the 4 layer or 6 layer bag in the same size. We do not state hours of cooling, because the result depends on how full the bag is, how many gel packs you use and the outside temperature.
Because performance depends on your own situation, many customers work with tests. You can request a sample and compare it with the packaging you use now. If you want help, ask for advice and we will think along. All versions are listed in our insulated bag range.
The 70 x 70 cm 2 layer bag is stored flat: a pallet of bags takes the space of a few EPS boxes. The 2 layer bag is cushioning as well as insulating, so it replaces a separate protective layer.
Frequently asked questions about insulated shipping bags
What is the difference between a cool bag and an insulated bag?
None. Cool bag, insulated bag, thermal bag and coolbag are names for the same product.
Do the bags have a closing strip?
All 2 layer bags have a self adhesive strip. Other versions are closed with tape.
Can I use an insulated shipping bag without a coolant?
Not for chilled or frozen goods. The bag insulates, the coolant provides the cold.
Order insulated shipping bags
View our full range of insulated shipping bags in 2, 4 and 6 layers, in stock and made in our own production since 1972. For flat, small items by post, see our cooling envelopes. Not sure about size or layers? Request a sample.
Alle namen voor dit product op een rij vindt u in onze begrippenlijst.
