Hair dryer

A hair dryer is an electromechanical device used for styling or drying hair.

It works by blowing ambient air in hot or warm settings. This process allows people to have better control over hair shape. The heat helps accelerate the formation of temporary hydrogen bonds within hair strands. These bonds are powerful but very vulnerable to humidity. They disappear completely after a single hair washing. By using a dryer with brushes or combs, users can add volume and discipline to their hair.

The mechanism of a hair dryer involves several specific parts working together. Most models consist of electric heating coils and a fan. The fan is usually powered by a universal motor. The heating element is often a bare, coiled nichrome wire. This wire is wrapped around mica insulators for safety. Nichrome is chosen because it has high resistivity and does not corrode easily when heated. In many modern dryers, ceramic heating elements are used instead. These provide "instant heat," which reduces the time needed to dry hair.

Users can manipulate the airflow using various specialized attachments. A diffuser is an attachment used for fine, colored, or naturally curly hair. It diffuses the jet of air so the hair is not blown around. This allows the hair to dry more slowly and at a cooler temperature. Using a diffuser can help increase hair volume and reduce frizz. Conversely, an airflow concentrator makes the end of the dryer narrower. This helps concentrate the heat into one specific spot for rapid drying. Some models also include a comb nozzle, which features comb-like teeth for styling without a separate brush.

There are two primary types of hair dryers used in modern grooming. The first is the handheld dryer, often called a blow dryer. The second type is the rigid-hood dryer, which is frequently found in professional beauty salons.

A hood dryer uses a hard plastic helmet that wraps around the head. It blows hot air through tiny openings around the inside of the dome. This method provides an even amount of heat to the entire head at once. Additionally, some people use a hair dryer brush to add volume. These brushes can be static or they can feature barrels that rotate automatically.

The history of hair drying began in the late 19th century. In 1888, a French stylist invented the first hair dryer. This version was a large, seated model that attached to a gas stove chimney. It was not portable and required the person to sit underneath it. In 1911, Gabriel Kazanjian became the first person to patent a hair dryer in the United States. Handheld, household models finally appeared around 1920. Companies like National Stamping and Electric works helped bring these to the market. Early handheld models were quite heavy and only used 100 watts of power.

Since those early days, the technology has undergone significant improvements. In 1954, GEC changed the design to move the motor inside the casing. During the 1960s, the use of better plastics made dryers much more lightweight. Modern handheld dryers can use up to 2000 watts of heat. Safety has also become a major focus for manufacturers. In the 1970s, the U.S. Consumer Product Safety Commission established manufacturing guidelines. Since 1991, all dryers must use a ground fault circuit interrupter. This prevents electrocution if the device gets wet. These safety measures helped reduce reported deaths from blowdryers to fewer than two people per year by 2000.

Beyond simple drying, hair dryers offer several advanced functional features. Many devices include a "cool shot" button to maintain a hairstyle. This button turns off the heater to blow room-temperature air. The cold air helps set the style, reduces frizz, and promotes shine. Some dryers also feature ionic operation to reduce static electricity buildup. While manufacturers claim this makes hair smoother, the efficacy of this technology is a subject of debate. Interestingly, hair dryers have also been cited as an effective treatment for head lice.