ELI5: Explain Like I'm 5

Block heater

A block heater is like a cozy blanket for a car's engine. When the weather gets really cold outside, the engine in a car can get very cold too, and that makes it harder for the car to start. A block heater keeps the engine warm overnight so that it's ready to go in the morning. It's kind of like putting your pajamas on before bed to stay warm while you sleep.

The block heater is a small device that gets installed in the engine block (hence the name "block" heater). It's always connected to the car's battery and electrical system, and it has a cord that plugs into an electrical outlet. When you're ready to park your car and let it sit for a while, you can plug in the cord to the outlet and turn on the block heater. It sends a little bit of heat to the engine to keep it warm.

Block heaters are especially helpful in places where the winters are very cold, like in Canada or Alaska. They can also be useful for diesel engines, which are harder to start in cold weather. When you get in the car in the morning, you won't even notice that the block heater was doing its job, because the engine will be warm and ready to go. It's just like wearing a warm coat outside on a chilly day!