Yet if you look on the shelves of your hardware superstore, there are only ionization type detectors. That's because they are about $3 cheaper to make than photo detect type.

You can still get good quality photodetect or hybrid (both photo and ionization in one unit) smoke alarms from Kidde, First Alert, etc. but you have to order them online, like from Amazon.com , for example.

Mike Dayoub, developer of the SmokeShutoff power strip (uses photo detect)