"Peter Parry" wrote in message
...
On Mon, 17 Sep 2018 21:12:48 +0100, "Jim GM4DHJ ..."
wrote:

are optical smoke alarms better for less false alarms than ionising
ones...in practice I mean ? .....

No. Neither have significant false alarm rates. Both however can
suffer nuisance alarms, these are not false alarms but real alarms
produced by non- dangerous activities such as steam from a bathroom
or overheated toast.

Optical suffer more from steam, ionisation from the combustion
products of things like singed toast. Used and sited properly neither
should have a significant nuisance alarm rate (unless of course you
are prone to overheating toast with the toaster is in the bathroom
sink while you are taking a shower).


It is mainly cooking and toast that do it...I bought an optical one
yesterday and will replace the ionising one in the ground floor hall and see
if we can cut down the false alarms .....probably get one to replace the one
at the static caravan should work better there .....I found the ionising one
at the caravan to be a god send when we had a leak of raw gas which set it
off good style which was surprising as propane is heavier than air and I
have no idea how it set off an ceiling mounted optical smoke alarm .....
but glad it did