NBC NATIONAL NEWS — It's that time of year again, when we're all reminded to set back our clocks and check our smoke alarms to make sure they're working.
But did you know you might have the wrong kind of smoke alarm?
The most common type contains an ionized sensor.
It's good at sensing flames or heat.
It has two tiny electrically-charged plates inside.
When smoke comes between the two plates, it disrupts the charge and triggers the alarm.
The other kind is photoelectric, good at sensing smoldering fires that start with lots of heavy smoke but not many flames.
Inside the chamber, smoke can deflect a tiny light beam onto a sensor, triggering the alarm.
Photoelectric smoke alarms are growing in popularity because smoke causes more deaths in fires than the flames do.
Customers can also get a dual alarm with both types of sensors.
They're a little more expense though, and they're not required under most city building codes.