Building a heater into rear defroster blower hose

im thinking of a heating element that gets hot like a soldering iron and heats the air....i want it to look somewhat factory and be pretty small.

i would mount it inside a metal piece of pipe in between the blower and the rear defroster duct

now i need to find something that gets hot enough to make a difference and use dc power....about as much power as a grid defroster.....maybe a resistor would work...

2ohm 100watt resistor ...or 1ohm 200watt
running at 13.5volts ....dissipation would be 91watts+....amps would be 7+.....
wire to run it would be #14 or 12.
i think that could create enough heat to make the air warm....then with a variable switch i could raise and lower the voltage....a 75 watt bulb seems to make lots of heat and in a contained metal pipe it should be ok.

I dont like how big the resistor has to be at 200watts 1ohm
7"x3"

any input on something more compact or more economic will help......i live in a colder climate...i need a rear defroster...the blower doesnt cut it...i do use it