It is certain that aluminum foil itself is not a good insulator, because aluminum foil can conduct electricity.
Aluminum foil has relatively poor insulation properties. Although aluminum foil has certain insulating properties in some cases, its insulating properties are not as good as other insulating materials. Because under normal circumstances, the surface of aluminum foil is susceptible to oxidation or corrosion, forming conductive oxides or corrosion products, thereby reducing its insulation performance.
There is a close relationship between the conductivity and purity of aluminum foil. Generally speaking, the higher the purity of the aluminum foil, the better its electrical conductivity and the higher its conductivity. Therefore, in practical applications, aluminum foil is usually not used as an insulating material, but is more often used to make conductive parts or as a conductive material.
Aluminum foil is conductive. The conductivity of aluminum foil depends on its manufacturing process and purity. Generally speaking, the higher the purity of the aluminum foil, the better the electrical conductivity and the higher the conductivity. Under standard temperature and pressure, the conductivity of aluminum foil is usually between 35-50MS/m.
In fact, aluminum is known for its excellent thermal conductivity because it conducts heat so well. However, when used as a radiant barrier or reflective insulation, aluminum foil can effectively reduce heat transfer by reflecting radiant heat. If aluminum foil is placed with the light side facing out in an area where heat is to be reflected, such as behind a radiator or a window, it can help reflect radiant heat back into the room, potentially improving energy efficiency.
Although aluminum foil is not a good insulator in the traditional sense, it serves a very important purpose in other ways.