According to the National Fire Protection Association, for best protection, it is recommended that both ionization and photoelectric technologies be in homes. We’ve only found a few such devices commonly available, such as the Kidde PI9010 Battery-Operated Dual Ionization and Photoelectric Sensor Smoke Alarm. But we haven’t found any alarms with the trifecta of ionization and photoelectric smoke detection PLUS carbon monoxide detection. For now, we recommend that you purchase separate units so that all possibilities are covered.
Please note that it is state law in California for all homes with attached garages to have a carbon monoxide detector. Did you know that if you pull a permit for any work done on your home, the city/county inspector will look for fire detectors and carbon monoxide detectors? It really is for your safety, but if you want to pass inspection, even for a totally unrelated home repair, get smoke detectors installed in every bedroom and hallway. As for carbon monoxide detectors, they should be installed outside each sleeping areas of the home including the basement.