On cold winter days, there is nothing like the feeling of climbing into a vehicle that has heated car seats.
Not only do the seats instantly warm you up, but they also add a different level of comfort, especially when the temperature is below zero or when you have a backache.
Although some people could not live with a car that had no heated seats, it is still important to know if they use more of your vehicle's gas when you turn them on.
The answer is, yes.
Your car's heated seats run off of the alternator and this increased demand will affect your mpg. The amount of fuel used is likely not enough to be measured unless you are continuously heating the seats, which is often unnecessary once the car's interior is heated.