They are Ionized smoke alarms, inside them are ions that move back and forth between two metal plates. If the ion stream gets disrupted by smoke particles, they are supposed to go off. They don't always. We learned that sometimes the ion stream isn't disrupted by larger smoke particles, such as the kind from say a smoldering couch, but don't worry, the smoke particles put off by your toaster is likely to set it off, if it is working!
Enter our new wall bling. We had heat detectors and optical smoke alarms installed yesterday.
The optical smoke alarm works by doing "visual" scan every eight seconds. The second it sees smoke the alarm is set off, unlike the ion alarms which only get set off if the particles are the correct size to interrupt the ion stream.
Therefore if you have a fire, within eight seconds of smoke appearing these alarms sound. That gives you and your family a lot of time to get out of the house. The heat sensors are placed in areas that are typically hot to start with, such as attics, shops, kitchens, utility rooms.
By the way, yesterday before our new bling was installed, we put some paper into a canning jar, lit it, put the lid on and made some decent smoke. After awhile we took the lid off and Lindsay and I commented on how bad it smelled, but the old Ion smoke alarm never went off. The smoke filled jar, was placed less than five feet away from it.
The new system is pricey. We violated our principles of not buying anything on "credit" (we are making payments to the company, not to a credit card company however). Tim is feeling a bit of stress over that. However, we feel like it is a wise thing to do. And we should get a reduction in our homeowners insurance by having these put in. We will of course, pay it off asap.
Meanwhile, we are prepared for the possibility of a fire, and knowing that we will know about it long before there is toxic smoke and flames. With five kids in the house, we have talked about how to get out of the house, where to meet, etc...they know how to use the fire extinguishers.
We pray that this wall bling will never need to be used.