Frequently Asked Questions and Help Center

How Can I Keep My PlanetBox Food Cold, For How Long?

Last Updated: Jul 19, 2017 11:30AM PDT

Our boxes are not insulated however, all our bags are insulated and will fit the PlanetBox ColdKit which helps to keep foods cold.  

If you want your foods to stay cold until lunchtime, the best thing to do is to pack the refrigerated foods the night before and chill the entire lunchbox, without the magnets on it, overnight in the refrigerator.  In the morning add the dry foods, the ColdKit,
wipe any condensation from the top of the box and apply the magnets, and store the box inside the Carry Bag and you are set to go.  

Our ColdKits are not included with our lunchboxes but they can be purchased separately.  Here is a link to them -

The length of time that the box will stay cold is dependent on many factors - ie, what temperature it started out at, what temp it is being stored at, what type of ice pack you use, etc.  

We have tested our ColdKit in combination with the PlanetBox lunchbox and Carry Bag on a typical school day. By pre-cooling the PlanetBox in the refrigerator overnight and then placing it inside the Carry Bag with the ColdKit in the morning, a substantial lowering of temperature can be maintained.

The exact temperature maintained throughout the day will depend on the ambient temperature the PlanetBox is stored in for the morning, exposure to direct sunlight or shade, and the number of times the lunchbox is opened throughout the morning.

In our tests, a consistent 40° F temperature was maintained inside the lunchbox while the exterior temperature was 75° F through the morning hours. 40° F is a safe temperature to store perishable foods, according to the USDA.

If a significantly higher exterior (ambient) temperature is anticipated, then we would suggest using two cold packs – one placed below the lunchbox and one placed above – to sandwich the PlanetBox in a blanket of cold throughout the morning. As reminder, the ColdKit can only maintain the cool for as long as it remains frozen. To truly keep perishable foods from spoiling for long periods, store them in a refrigerator.

For more information on our lunch packing systems and what to expect, check out our video:

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