What are those metal things called on top of your home that spin around when the wind blows?

Question

They are silver in color and there are usually two of them. I think it is some kind of ventilator, but don't really know what they are called

Answer 1

It's a whirly bird. For venting your attic.

Answer 2

wind vane maybe? i know I'm close.   WEATHER VANE!

Answer 3

These Wind vents are especially important in order to circulate the attic air.  This will generally help to cool your home in summer, and during the winter they may be closed from the inside, or covered with plastic on the outside to prevent heat loss.

Answer 4

Wind turbine Vents

Answer 5

A WIND MILL.......

Answer 6

They are a type of vent.  When I looked it up on the web it said they are just called roof vents.  One place called them a roof turbine vent.