Honestly, HVAC is a fantastic industry with plenty of room for innovation. This being said, there's far more accurate automation in industrial applications than around the home. A good example of this work is within airports and casinos. The new Vancouver Convention Centre is something worth reading up on too.

For technically-inclined individuals, understanding how water, air and gas move is the ticket to a proper disruption. This goes beyond the bandaid fix of a good, intuitive thermostat, and into the circulation of fresh air and overall design of the home.

I will say though, that smoke detector is awesome. Here's hoping that Google doesn't just shut down the good work that's been done.