The song was the last track to be recorded for the album Eyes Open and was the third single released from the album. It was written especially with Martha in mind. Lightbody wrote the song in only 20 minutes and described it as the quickest he had ever written a song. The song title describes an electric heater. While writing in the freezing cold and wearing fingerless gloves Lightbody recalled that as a child his Aunt Jean had an electric heater, and "if we were very good and it was very cold, she'd let us put all three bars on" and he goes on to say how it represents "a beacon of warmth within a song about distance"