[raldi]

False dichotomy. With an extra ten cents' worth of technology, the smoke detector could do its initial chirping quietly and during daylight hours. If you ignore them, then later it can escalate to around-the-clock 85-decibel alerts.

Ditto sensitivity. At the first wisps of a problem, give a gentle sound. If it gets worse, or 60 seconds pass, then get shrill.

Re: "how many do you need in one area?" the last three words do not apply. The low-battery chirp is loud enough that a dying battery anywhere in the house can wake you up. For the record, though, we were required to put one in every bedroom and two in our small hallway -- and that's just on our upper level.

[danparsonson]

Have you seen how quickly an actual house fire takes hold? There are videos of fire department demonstrations on YouTube (http://www.youtube.com/watch?v=rUh4rCjuYDA for example). In sixty (or even ten) seconds of gentle sounds, you'd probably be dead. Not to mention that smoke can take time to rise up to smoke detector level - crucial seconds that you could be using to escape rather than comfortably waking up.

As for the low battery chirp, it should be annoying - that way you attend to it rather than leaving it until later. And chirping only during the daylight hours - how is that helpful if you're out at work? The battery will be dead before you even know about it.

Smoke alarms should be intrusive when they need your attention. That's how they save lives.

P.S. as for the last point - I was actually referring to how difficult it is to work out which smoke detector is chirping. Thus my question - I can't see how it's difficult unless you have lots of smoke alarms. Badly explained on my part, sorry.

[raldi]

> In sixty (or even ten) seconds of gentle sounds, you'd probably be dead.

Which is why I also said that, if the problem gets worse that just a few wisps, the detector should immediately escalate to full alarm.

> And chirping only during the daylight hours - how is that helpful if you're out at work? The battery will be dead before you even know about it.

Again, it can start quiet and polite, and then escalate to more aggressive notifications if you ignore it.

[danparsonson]

> Which is why I also said that, if the problem gets worse that just a few wisps, the detector should immediately escalate to full alarm.

Indeed, but personally I don't want a dumb electronic device to make that judgement for me - I'd like to do it myself. I'll know instantly whether or not the house is on fire and I'd like to know instantly whether or not it seems like it might be. False positives are, as I said earlier, infinitely preferable to "he'd have made it out if he'd heard the alarm earlier". Besides, how do you decide what's "house fire smoke" vs "burnt toast smoke"? if the fire isn't adjacent to the detector then smoke may only reach the detector slowly.

I get the drive to make devices more intelligent and thus more convenient but I strongly disagree that this philosophy should apply in all cases. Sometimes 'basic' really is better. Not to mention that there's less to go wrong.

[raldi]

> Indeed, but personally I don't want a dumb electronic device to make that judgement for me

But ultimately, you have no choice. Even the ideal smoke detector that you have in mind is going to be a dumb electronic device that has to make a judgement for you.

It'll have some sort of threshold before the loud alarm goes off. I'm not suggesting that be changed.

What I'm suggesting is that, in addition to that, at an even more sensitive threshold, there be a quieter alarm, too.