Frank was thinking very hard :
On 11/30/2020 8:41 AM, FromTheRafters wrote:
Sid 03 expressed precisely :
Looking to install some new smoke detectors.* I was going to install
Ionization type smoke detectors in the lower floors and then a combination
smoke and CO* detector on the 3rd floor where the bedrooms are located.

I noticed that most of the combo detectors do not use ionization to detect
smoke, but use photoelectric type sensors.** Is this a a big deal or
should I stick with the most popular ionization type ? Years ago I was
told by a contractor to not install combo detectors, but to keep the CO
and Smoke detectors separate ? Does anyone have an opinion on that ?

If the CO detector has an interconnection wire for other alarms, should
you connect it to the interconnection wire for the fire-Alarms ? All this
stuff is manufactured by Kidde, so I am assuming that is all compatible ?

Thanks
Sid.

CO is heavier than 'air'. Smoke is generally in hot air and rises.-- follow
their instructions for placement.

Heavier?

CO 28.01 g/mol
N2 28.0134 g/mol
O2 32.00 g/mol

I stand corrected. Smoke rises, and CO, generally, does not.