No one gives it a thought today.  If your car is too cold, then simply switch on the “heat” and soon your car will be nice and warm.  It wasn’t always that way, though.  In the early days of motoring, most cars didn’t have heaters.  Back in those days, cars were essentially open carriages with motors. What passengers did was bundle up as if one was staying outdoors. This meant heavy clothes, winter gloves and snow boots.  It wasn’t long, however, before car manufacturers realized that a few creature comforts, like enclosed cabins and heat in the passenger compartment, would help sell cars.  As you might imagine, though, the technology evolved as cars became more popular and advanced. Thanks to an excellent article on the Central Avenue Chrysler, Dodge, Jeep, RAM of Yonkers, NY website, here’s the story.

Heat from hot bricks

The earliest car heaters were rather odd.  In the early 1900s, devices called “heater boxes” were popular. They were low-profile metal boxes covered with a carpet-like fabric that you could slide a heated brick into.  The bricks were typically heated in an oven or fireplace before trips.  After the hot brick was placed in them, they would then be placed on the floor of the car and would help heat the feet and legs of the driver and passengers. Heater boxes were a little crude but they provided a little relief from the bitter cold.

Heat from the exhaust manifold

Engineers soon realized that a lot of heat was being generated by the engine and blown out the tailpipe.  The result was that during the 1920s, several manufacturers designed special exhaust manifolds that allowed some of this exhaust heat to be funneled into the passenger compartment.  This was accomplished by casting a second passage above the engine exhaust ports that connected directly to the passenger compartment. These “heater manifolds” could throw out a lot of heat.  Back then there weren’t any dash controls or electric fans to distribute the heat so what you got was a ton of heat, all the time.  This type of heater was a solution to the problem but not a very good one.

Heat from the cooling system

In the 1930s, engineers turned to the radiator and coolant system.  It was simple, they ran the hot coolant developed in the engine-radiator system into a “small radiator” located under the dash and an electric fan blew it throughout the cabin.  This was the beginnings of the modern automotive heating system.

Today’s Heating/Cooling Systems

Today heating systems are integrated with air conditioning systems so that the temperature of an automobile’s cabin can be controlled regardless of what temperature.  If heat is needed, then the heater comes on. If it needs to be cooled down, then AC comes on. These systems are complex with lots of heating/cooling ducts, vacuum motors and sophisticated electronic control systems.   When it comes to the heating portion of these systems, though, the basics still apply.  The hot air that comes out of a new car is still heated by the engine’s radiator coolant system.  It is just done so with a myriad of 21^st century technology.