They used to make, (maybe they still do) units that connected inline in a heater hose. It had a circulator motor that ran on 110 VAC. It kept the coolant warm and circulated it through the engine. I guess that's fine as long as you have 110 available.

 

all our equipment and trucks have block heaters. Glow plugs work just as fine in our diesels tho.

I think a block heater or remote start is best for a gas motor.

 

is shown in the video disel in fact, was supposed to illustrate just what it needs. My unit is on gasoline. the benefits of this are that:

First you do not need to run all over the engine
Second demand for gasoline is only my device 0.178 gallons (0.670 liters) for 1 hour of work at max, when it warms all just need 0.100 gallons (0.370 liters) for 1 hour of work
3rd switching devices will be 30 minutes before driving a car, for example, before work, after work, etc.,
it can also be use as heating when the vehicle is not running.
I do not know what it's like in the U.S. but in Europe in cold countries it is very popular.

The device will be mounted on the programmer enters a program will be an hour off the device, or to make it remotely.