Why Is Aluminum Foil a Better Insulator Than Cotton or Paper?

Adding insulation to your home is an easy way to save on energy costs. Aluminum foil, also called tin foil, makes an excellent insulator, and in some situations, it works better than materials like cotton or paper. Aluminum foil is not best for every situation, though, so using it correctly is an important part of saving energy.

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Cover a window with aluminum foil to keep sunlight out.

Identification

Simply sheets of pliable aluminum that are less than 0.2 mm thick, aluminum foil has several household uses. Some companies manufacture long, stronger strips specifically for insulation, but you can also use typical aluminum foil to insulate. If the foil is particularly thin, companies will sometimes laminate it with plastic, paper or other materials to make it stronger.

Benefits

Because aluminum foil reflects light, it can be used for insulation, especially in areas that need to be guarded against heat. When it is used with other materials, it can be used to warm an area, too. Other materials such as paper and cotton, do not have the reflectivity that aluminum foil does, so when the sun is bearing down, they will not keep it out as well. An area that is already hot will be kept hot by aluminum foil, as it will hold in hot air. Paper and cotton will release heat at a quicker rate than aluminum foil. Aluminum foil can keep things like wires or pipes insulated, as it traps air when it is wrapped around an object. This can be achieved with several objects, though, and not just aluminum foil.

Using Aluminum Foil

Insulating a room in the summertime with aluminum foil can help keep sunlight out of the room and lower temperatures. Completely cover all windows with aluminum foil and secure it with a heavy-duty tape such as duct tape. The shiny surface will reflect the sunlight's rays. You can also insulate cold food when it will be near the sun. Wrapping a cold soda can, for instance, with aluminum foil will keep it chilled. Adding a layer of bubble wrap between the aluminum foil and soda can will keep it cooler for longer.

Considerations

If you would like to insulate something in a dark place, such as lunch box, another material such as cotton or paper could work just as well as aluminum foil. As a matter of fact, cotton is regularly used for insulation, as it is environmentally friendly. Because aluminum foil reflects light, when it is in a dark place, there is no light for it to reflect, so it will work similarly to other materials.