There are systems like Ventis and others that will use the external air or ceiling air when suitable to heat or cool the house (see my post at

I'm not sure what you are referring to. I wrote a blog about trying to reuse the air in the ceiling and discovered a company called Ventis that does it…

For years I've been contemplating how to make the most of the hot air in my ceiling and the cool air under the house. I've blogged about it a number…