My 1400 sq ft ranch house (zone 5a, CT) is shaped like a “T” – the living space is on the top of the T, the sleeping space is in the “body” (a hallway) of the T. 

In the living space, 3′ away from the hallway, is a large fireplace insert that heats the house well for most of the winter, as long as all of our bedroom doors are open (which the teens hate).  In summer, we have two window air conditioners, one in the living space almost directly facing the hallway, and one at the other end of the hallway, which keep us cool.  We use fans to blow the air around effectively.

Does anyone have experience with hardwired through-the-header room-to-room fans? These seem like a great solution – we could install them over each bedroom door and over the hallway door, allowing us to close our doors at night and move the air without fans all over the place. I have seen these fans in 100 year old homes – why aren’t they used today?  Are they quiet? Effective?  Efficient?