A remote car start system uses a wireless transmitter to activate the starter on a vehicle, eliminating the need for a driver to place a key in the ignition switch and turn it to start the car. The wireless transmitter is often in the form of a key fob, similar to a keyless entry device. Using the remote start system, drivers can start and warm up the vehicle so that its components are warm before leaving the driveway.
On frosty mornings, the remote start allows the driver to start the car so that it defrosts without the driver having to leave the house. Once he arrives at the car, the passenger cabin is warmed for a more comfortable commute. When outdoor temperatures are hot, the driver pushes the start button and starts the air conditioning, cooling the vehicle from inside a cool house.
As of 2015, some manufacturers are offering remote start as a feature on their new cars, but the feature started out and remains available as an aftermarket addition. It is sometimes tied to the keyless entry and uses the same fob for starting and unlocking the doors. Some systems allow owners to use their smartphones to operate the starter. Systems may also allow the user to disable the starter as an antitheft feature that requires use of the remote to start the car.