Generally speaking, coolers are primarily designed to keep food and beverages cold to extend their freshness. Therefore, the primary function of a cooler is to keep it cool, not warm.

Refrigerators usually use insulation materials to reduce heat transfer, such as polyurethane (PU), polystyrene (EPS), etc. These materials have good thermal insulation properties and can effectively slow down the transfer of heat to the items inside the box. Therefore, a cooler can help keep food and drinks cold for a certain period of time.

However, since the refrigerator is designed to keep cold, its thermal insulation is relatively poor. Hot boxes are specially designed to keep food and drinks warm. These thermal jars typically feature better insulation materials and structures to provide better insulation and maintain the temperature of food and beverages.

If heat preservation is required, it is recommended to choose appliances specifically used for heat preservation, such as thermos jars, thermos flasks, etc. Using materials and structures that are more suitable for thermal insulation, food and drinks can be better kept warm.