Ask HN: What kind of challenges do hardware startups (like Nest) face?

I was reading the article posted today about how supposedly it's near impossible to have one's hardware solution accepted into a hospital. Folks mentioned that the challenge is indeed great for most hardware devices, not just the medical ones.

A few friends and I have been discussing a device + cloud hybrid solution, vaguely inspired by Nest. We were wondering how big of a hurdle a company has to overcome in order to get a physical device into someone's home.

We'd love to know what we're getting ourselves into before we spend too much time on that path.

Thank you!