The forerunner of the modern electric blanket was designed in 1912 by American physician Sidney Russell. In trying to devise an effective heating pad for his patients, Russell found that he could produce the desired heat by passing an electrical current through insulated metal tape that had been secured inside a blanket covering. It was not until the 1930s, however, that the electric blanket was commercially developed in the United States. Sometime earlier, in 1926, the British Ex-Services Mental Welfare Society acquired the rights to the Thermega Underblanket, but did not begin producing it until about the same time American manufacturers introduced electric blankets.

Safety was a major concern in electric blanket use. Research conducted during World War II on electrically heated uniforms for airplane pilots led to some safety improvements to electric blankets--most notably the addition of protective vinyl coverings for the electrical elements. In 1967, after a series of accidents, a U. S. company called Dreamland incorporated a monitoring system that cuts off electricity to the blanket if it overheats. In 1970, Britain's Thermega marketed a blanket that replaced the electrical elements with tubes carrying hot water.

Current (1998) research results on a possible relationship between electromagnetic fields and various cancers are uncertain, although prudence dictates taking reasonable precautions when using electric blankets. Although newer blankets have better shielding and use less electricity, heating the bed then unplugging the blanket for most of the night seems a sensible approach.