> All this due diligence and much more was done. I don't have any connection with Nest Protect and don't own one, but the fact that the Protect does not use an

> All this due diligence and much more was done. I don't have any connection with Nest Protect and don't own one, but the fact that the Protect does not use an ionisation sensor (they suck because they suck at detecting fires early, it has nothing to do with the harmless radioactivity) and used a dual-wavelength photoelectric sensor gives them high marks in my book. All the hardcore smoke detection equipment -- both the aspirating kinds ("VESDA") and the open-space beam/imaging kinds -- use dual-wavelength sensing. I cannot speak to all the "smart"/"connected" aspects of the device but the smoke sensor seems far better than that of every other residential smoke detector, and it would be very nice if other residential smoke detectors ditched the ionisation sensor and went to a dual-wavelength design.