Nico Mertens came up with this idea when he asked his friends about leather seating. The women he questioned said that they liked how leather seats looked, but didn't like sitting on them because they got cold. This revelation led him to install a heating system into his IKEA Poang chair. While he was doing this, he also extended the headrest so that it would fit his height.
In order to deliver the heat, you'll need an extra cushion to make a strap for the electrics, a seat heater which could come from an electric blanket or a heat pad, a notebook power adapter that gives out between 12 and 13.5 V and up to 7 Amp, and some odds and ends to make the chair look good. The seat heating was basically sewn into the seat cushion. Nico added a nice little piece of wood to serve as a place to insert his seating button, which obviously was salvaged from a car, just as his seat heater. The whole chair was sanded down and repainted so that everything would match. The best thing is that he got an offer of $1,500 for his pimped out Poang chair.
[via IKEA Hacker, photos by Nico Mertens]