Electronic engine heaters (not to be confused with electric heaters to shut off cigarette joints) are a cheaper and more environmentally friendly alternative to the classic stationary heating system. This system is especially useful if you have a power outlet installed in a parking lot and you usually only drive short distances in your car. You can see some car engine preheaters via https://www.hotheadheater.com/.
It's easy to explain: a cold car produces the same amount of radiations as a preheated engine within 300 kilometres within thirty seconds of starting. The engine heater range is quite large. Popular models are HOTHEAD JR PRO, one of the most expensive alternatives but also the best quality. Such a system works similarly to an immersion heater.
The preheater is usually located in the hole in the frost plug in the engine compartment. This method of installation means that the engine heater is removed from the coolant of the vehicle and can warm slightly. This is why systems are also popular as the term for cooling water heating.
When the device is switched on, the entire motor housing gets hot. This system significantly reduces engine friction when the vehicle is started and not only reduces engine wear but also reduces fuel consumption and pollutant emissions.