Q. I’m new to Honda and I don’t know how long I should leave my vehicle plugged in for. I’ve heard that I should use a timer to have it turn on early in the morning before I leave for work. Wouldn’t plugging it in overnight be better, make it warmer inside my car?
A. This question comes up often, usually when the weather turns colder. (We’ve been lucky this year, but now that winter has settled in…) The engine block heater is designed to do just what its title suggests: heat the engine block (a bit). The block heater element is located in the coolant passages surrounding your engine block assembly. When supplied with electricity, it produces heat from the element. This will transfer to the coolant and slightly warm it up (anywhere from 5 to 15 degrees Celsius). The warming of the coolant, and thus the block assembly, makes engine starting easier, and shortens engine warm up time a bit. It does NOT warm the interior of the car, nor does it generate enough heat to have warm air flowing from the heat vents right away. Its only job is to help cold starting, really. Once the engine block heats up to a certain point, determined by the outside air temperature and any air motion in the area, the heat generated becomes lost to the surrounding air. That’s why plugging in your vehicle overnight is wasteful; the heat generated is just lost to the cold air surrounding the engine. Not the best use of electricity. Once the block heater has been operating for about 40-55 minutes, any heat generated becomes wasted. That means plugging in your vehicle 30-50 minutes before you plan to start it is the best use of the energy and heat. And this is where the timer comes in; you don’t have to go outside to plug in your car in the early morning cold if you set a timer and plug in the night before.
