Who invented the electric heater?

Some attribute Thomas Edison as the inventor of the electric heater because a light bulb creates both heat and light. However, Heater Home claims that Albert Marsh discovered chromel in 1905, which was used to create the first heat element.

Chromel, which is made of four parts nickel and one part chromium, was 300 times hotter than other heating elements at the time of its discovery. For his discovery and invention, Marsh was termed the "Father of the electrical heating industry," according to Wikipedia. He worked with William Hoskins at a company of consulting chemists for several years while perfecting the alloy. The material was then patented in 1906.