Review on X-Sense SC08 10-Year Battery Smoke and Carbon Monoxide Detector with LCD Display, Dual Sensor Smoke and CO Alarm, UL 217 & UL 2034 Compliant, Auto-Check Technology by Chad Siofele

My old carbon monoxide and smoke alarm used 3 AA batteries which seemed to run out in the middle of the night and made a chirping noise. He started tweeting at 4am scaring my dog and waking everyone up. After replacing the batteries didn't stop the chirping, I removed it to find instructions on the back stating the unit died in 7 years and needed replacing. This new device lasts 10 years without changing the battery until the device fails after 10 years. It has a handy LED display so you can see the actual level of CO in the air (luckily it's 0). At $31, I calculated that it would cost about $3 a year to keep us out of commission for the next decade.