Butch Haynes wrote:
"Myrna" wrote in message
oups.com...
In our home there are 3 smoke alarms, all wired into the house wiring.
All are the same age (about 22 yrs). There's a high pitched noise
coming from one of them.

In a recent discussion, one guy told me to replace all of them, not
just the one. He said new ones aren't compatible with the new ones. I
didn't ask him what he meant about being compatible.

So, can anyone tell me what this means? Do I have to replace all 3?

Thanks,
Myrna


Fire departments recommend using battery operated ones that are independent
of house current and could be compromised in a fire.


I'd like to see a reference for this claim. I've seen lots of news
stories where people died in fires where they either did not have any
smoke detectors, or else had ones with dead or removed batteries.
I've never read a story about anyone dying in a fire due to the power
to the smoke detector being taken out by the fire. Here in NJ all the
new construction homes I see have AC powered units, as does my home.
It's a theoreticaly possibility that the power to the smoke detector
could be lost in a fire before the alarm goes off, but IMO, that risk
is very small compared to having a dead battery.