Different kinds of insulated coolers (material, geeks)

[snowmountains]

Insulated cooler bags on the market are made of a variety of materials for the purpose. Some have aluminum foil interior, others have white plastic lining covering some other materials (Polyethylene, Polyurethane, Polypropylene). See pix. So my questions:

1. Which type is better for keeping heat?
2. Which type is better for keeping cold?
3. Is a cooler that is better for keeping heat also better for keeping cold?

My impression is the aluminum foil type is usually for keeping food hot, and the whitish ones usually for keeping food/drink cold with an ice pack, but I'm not sure why, if so.

[DPolo]

I do believe that materials are rated by their insulation properties. The higher the insulation rating the longer the food stays at needed temperatures.

It would be helpful if sites like Amazon would be more technical, for geeks like us.

[Malloric]

Insulation is basically insulation, doesn't much matter whether you're keeping hot out or in. Cold is generally easier since the relative temperature difference is less. Eg, if you're trying to keep something cold room temperature is only about 21-22C. If you're trying to keep your coffee hot, most people want it around 75-80C. Bigger differential.

Amazon.com: Zojirushi SL-JAE14SA Mr. Bento Stainless Steel Lunch Jar, Silver: Bento Boxes: Kitchen & Dining

Thermos makes some similar things. They'll knock the socks off your insulated lunch bags, but they're really over kill if you just want to through an ice pack in and a sandwich.

[thecoalman]

Heat moves in 3 ways; convection, conduction and radiation. Heat also always moves to cold, when you hold an ice cube in your hand the ice doesn't make your hand cold, it's sucking all the heat out of your hand. The foil may help with the radiation of hot foods but most of your heat loss is going to be through conduction. The insulating material itself is going to be the main factor and it's going to be the same for hot or cold.