I had in all smoke detectors (3-Pack) now several false alarms, usually at night (dust by sweeping or vacuuming therefore applies not), also we are a Non smoking household. These smoke detectors are unsuitable. As soon as the alarm went off, my first thought was not at the end: "Oh dear - it burns!" but "Not again ...". That can cost valuable seconds in an emergency and endanger lives. And then they are no matter how outrageously expensive. I have them all removed and returned.
I would give it no star, but unfortunately is not. The one star deserves because he has refunded me the smoke alarm dealers. Thanks!