An electric water pump may not seem like a very big deal, but it’s one of my favorite things about the 2010 Toyota Prius engine.

Making the water pump electric, rather than running off a belt driven by the engine’s crankshaft, holds a few benefits. First, there’s the practical benefit of reducing the drag on the engine. This means none of the engine’s power goes to turning the pump impeller, and that reduces drag. But Toyota also points out that by making the water pump electric, the ECU can more precisely control the flow of coolant through the engine. It can also run the water pump independently of the engine, allowing heat to flow even when the car isn’t running. Provided there’s enough hot coolant, of course.

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