There is a big difference. House paint is designed to adhear to wood. Automotive paint is designer to adhear to metal. If you paint a vehicle with house paint, it will fade quickly, won't shine very well and peel off. It is not designed to "bite" into the metal. It is also not designed to handle the extreme weather conditions that an automobile paint finish has to endure. For example.. high speed winds, high speed rain, road salt, ect.. Automotive paint is also thinner than house paint. I would not recommend painting your car with house paint. It will be very expensive to repair the damage to the exsiting paint.
