In the U.S and Canada, an electric blanket is a blanket with an integrated electrical heating device usually placed above the top bed sheet. In the U.K and Commonwealth, electric blanket commonly refers to an electric under the blanket (electric mattress pad), which is placed below the bottom bed sheet. Electric blankets usually have a control unit which adjusts the amount of heat the blanket produces. Blankets for larger sized beds often have separate controls for each side of the bed. The electric blanket may be used to pre-heat the bed before use or to keep the occupant warm while in bed.
Some modern "low voltage" electric blankets have thin carbon fiber wires and work on 12–24 volts.
The first electric blanket was invented in 1912 by American inventor Samuel Irwin Russell. This earliest form of an electric blanket was an ‘underblanket’ under the bed that covered and heated from below. There is some dispute about when the first electric over blankets were introduced. The first recorded publication of such a unit was in 1930 by Samson United Corporation. However, others claim it was later in 1937 that electric 'over blankets', which lie on top of the sleeping person, were introduced in the United States.
Much like heating pads, electric blankets use an insulated wire or heating element inserted into a fabric that heats when it is plugged in. The temperature control unit, located between the blanket and the electrical outlet, manages the amount of current entering into the heat elements in the blanket.
Some modern electric blankets use carbon fiber wires to heat the user. These wires are far less bulky and conspicuous than older heating wires. Carbon fiber wires are also used as the heating element in many high-end heated car seats. Blankets can be purchased with rheostats that regulate the heat by managing body heat and blanket temperatures, ensuring a comfortable experience.
Newer electric blankets have a shutoff mechanism to prevent the blanket from overheating or catching fire. Older blankets (prior to about 2001) may not have a shut-off mechanism; users run the risk of overheating. Older blankets are considered fire hazards.
Some electric blankets work on a low voltage of 12 to 24 volts, including those which plug into ordinary household electrical outlets; in the US, such blankets are sold by Soft Heat, Serta, and Select Comfort. Such blankets also include 12-volt blankets designed for in-car use; they tend to shut off automatically every 45 minutes or so.
Old or damaged blankets concern fire safety officials internationally. The use of such blankets is of concern due to the combination of heat, electricity, the abundance of flammable bedding material, and a sleeping occupant. In the UK, it is estimated that 5,000 fires per year are caused by faulty electric blankets, of which 99% are believed to have been caused by blankets 10 years or older.
Electric blankets also present a burn risk to those who cannot feel pain or are unable to react to it. Individuals included in this group are small children, diabetics, and the elderly.
As with any source of heat over the groin, use of electric blankets can reduce fertility in men.
There is little scientific evidence to support concerns that electromagnetic radiation from electric blankets may cause negative health effects.
A cartoon electrical blanket with its electrical temperature control acting as an anthropomorphic face named "Blanky" was portrayed in the 1987 film The Brave Little Toaster.