False alarms are usually down to incorrect sensor type selection and/or incorrect siting of the detectors themselves.
I have 16 interlinked detectors comprising of several different sensor types, ionisation, optical and rate of temperature rise and CO sensors.
In the 7 years since installation, there has never been a false alarm due to cooking, toasters,running a wood burner, steam from bathrooms/showers etc.
The times it did go off were due to:
A CFL lamp burning itself out before finally failing and hot work involving the soldering of copper pipes....
S.