Lots of people have electric blankets, but I used to have an electric sheet.
When I was a kid we lived in a little cabin in the hills. The original owner had built it himself in 1913 as a summer cabin. It wasn't insulated and only had a gas heater in the living room. It didn't snow where we lived, but the bedrooms still got very cold in the winter.
When my father died my grandfather came to live with us so my mother could get a job and the tiny bedroom at the back of the house became his.
My uncle was an engineer for PG&E and back then they wanted people to use as much electricity as possible. He helped develop a contraption called an electric sheet and gave the prototype to my grandfather. I'm not sure if that was in the late 1940s or early 1950s.
The electric sheet was made of seersucker with zig-zagging wires sewn into it. It couldn't be washed, but was supposed to be placed between the top sheet and blanket so it wouldn't have contact with the skin and would stay clean.
Years later when my grandfather had to go to a nursing home the electric sheet became mine and I used it for about ten years until I got married. By then the thin fabric was dirty (it didn't always stay between the sheet and blanket,) threadbare, and torn.
Of course electric blankets had been invented in the meantime so my husband and I got one and have used those ever since. I'm so glad they can be washed.