Reversing valve

Do you ever use a straw to suck up juice from a cup? A reversing valve is like a straw that moves things back and forth. It's a part of an air conditioner or heat pump that helps switch the direction of the air flow.

When it's hot outside, the reversing valve makes the air conditioner take hot air from inside your house and blow it outside. But when it's cold outside, the reversing valve can make the heat pump take the cold air from outside and bring it inside where it gets warmed up.

So, just like the straw switches the direction of the juice flow, the reversing valve switches the direction of the air flow in your air conditioner or heat pump.