Water has a high specific heat capacity. Specific heat capacity is defined as the amount of energy it takes to raise 1 ml of a substance by 1 degree Celsius. Since water is high, it take a large amount of energy to raise its temperature. That is why it is a good insulator.

Plastic, rubber, wood, and ceramics are good insulators. These are often used to make kitchen utensils, such as saucepan handles, to stop heat from flowing up to burn the cook’s hand. Plastic coating is also used to cover most electrical wires in appliances. Air is also a good insulator of heat.

Which Metals Conduct Heat The Best?

Is Aluminum Foil A Good Insulator? In fact it is not, Aluminum foil itself is a good conductor of heat, directly used basically has no heat insulation, but accelerate the heat loss, so when used the insulation cotton is wrapped inside the aluminum foil.

Strictly speaking, “tin” (aluminium) foil is a very poor insulator. It conducts heat very well. Even so, it reflects radiant heat very well, so is used to create emergency blankets (“space blankets”) for hiking for that reason. To conduct heat, metals must be actually in contact with the thing that’s hot.

In short, the answer is yes, polyester will keep you warm when combined with good other fabrics like wool and cotton. But, polyester can also allow breezes to pass through and keep you cool.

Although spandex is used in a wide variety of outfits and circumstances, it does not have a warming effect. But it can be combined with cotton or polyester– which are not very warming, or wool which can keep you warm. In fact, the percentage of spandex is small – around 2-10%.

Polyester and polypropylene are moisture-wicking fabrics, which draw perspiration away from the skin. They make great cold-weather clothing.