Lunch Bag Insulation

Back in the day, our lunches were packed in classic brown paper bags or plastic lunch boxes. As things progressed and became more modern, trendy lunch bags began to emerge with the environment in mind. Among these wonderful innovations are insulated lunch bags. They are able to keep food and drinks cold or warm/hot—depending on what's in it, of course—for a longer time than the traditional lunch bags. More importantly, they help prevent food from turning stale.

You may be left wondering how this is achieved. You're not alone; read on to find out more.

How do lunch bags with insulation work in the first place?

Majority of insulated lunch bags are equipped with insulation in multiple layers. This is generally comprised of an outer layer and a lining, then the middle layer where the insulation happens. The middle layer is incredibly crucial since it makes all the difference between an insulated lunch bag and the standard kind on the market.

There is a vacuum factor that insulated lunch boxes and thermoses depend on, usually created between inner and outer layers to avoid energy dissipation. In contrast, food and drinks are kept cold or warm/hot by insulated lunch bags through the core layer. The aforementioned layer is made of foam that is quite dense and thick. The denser and thicker it is, the more insulation intensifies. 

With that foam layer, heat does not end spreading to the outer layer. It prevents the heat or cold from spreading elsewhere. This is why an insulated lunch bag’s exterior does not end up hot or at least warm to the touch, even when it's filled with hot food items. There is a wide range of materials used for the outer layer of lunch bags: heavy fabric, non-woven fabric, or vinyl. The inner layer is also lined with foil, heavy vinyl, or even heat-reflective or waterproof plastic. 

What does it mean to have a heat-reflective inner layer?

This generally refers to the inner layer of the lunch bags, aiming to reflect the thermal energy which food radiates back to it. This is instead of letting it escape the bag through absorption. This helps food stay at its original temperature and retain its initial flavour. Where applicable, it's also able to retain the food's moisture for much longer than a regular bag would have done.

With all that in mind, it's safe to say that when you use an insulated lunch bag, food will also be prevented from going stale. This is similar to the way wrapping food in tin foil works.


Aside from being trendy, using insulated lunch bags is a great way to keep your food cold or hot/warm for much longer. It can do this through multiple layers, particularly the core layer made of foam that is quite dense. They're also sustainable lunch bags, which means they are incredibly helpful to the environment. With an insulated lunch bag, you can have lunch in style and enjoy your food at the right temp, all while being mindful of your carbon footprint.

Are you searching for insulated lunch bags? Check out Ru Supply Co today! We have stylish, cute, and professional-for-work lunch bags for adults that are ethically made in Canada.

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