(I have carbon monoxide detectors that are not going off)
I have smoke detectors that are incorporated into my home alarm system. The other day, the one by my front door went off for no apparent reason, twice, and when I changed the batteries, it started alarming again immediately.
there was absolutely no reason for it, there were no open windows or doors nearby, it just went off. so, my alarm company replaced it. installed the new smoke detector yesterday and… it just went off again. completely different smoke detector.
there’s absolutely nothing in my house that could produce carbon monoxide, but I have separate CO detectors anyway that aren’t going off. there’s no smell, there’s nothing visible, and these are those electro optical photoelectric style ones.
Are your smoke detectors linked to each other? Could be faulty wiring in the circuit, or a completely different smoke detector failing and sending out an alarm that triggers the others. The latter happened in my home when I was growing up: the living room smoke detector kept going off a few seconds before the rest of them would chime in, but it turned out it was the one in the nearest hallway that was failing and sending out bad signals. The living room detector was just the next in the circuit.