I would agree with Spyder, the only way to protect a house, is to inter-connect the whole lot, if one goes off, the whole lot do.
And run the lot of them off the mains, most people never change the batteries in these, until the "Low Voltage" chirp, starts, by then it is far too late to expect a S/Detector to give a decent Decibel output.
It takes 110dB to wake a sleeping person, a
detector with a low voltage(half discharged
battery), will struggle to make 80dB.
Bear this in mind, you can't smell smoke when you are asleep!.
Smoke detectors do save lives, but only when they are maintained properly.
Would love to see a decent system, that prevents us Firefighters, dragging, burn't,
dead bodies out of House Fires, in the middle of the night!. [Linked Image]