Home Improvement → Re: How often to change smoke detector batteries

Most fire dept's recommend changing the batteries twice a year, at the start and end of daylight savings... Probably a little excessive, to be honest; but better that way, then the other. I keep the batteries I take out of the smoke detector, and use them in other things, as not to waste them...

There are some lithium batteries out now that last 7-10 years, as well.

No matter how they are powered, smoke detectors should be replaced every 10 years at a minimum, 7 years for CO detectors... Some detectors now include a lifetime counter, and start chirping when 7-10 years (as appropriate) has elapsed...

That's is built into any unit after March 2007.

CO Alarm
"Seven (7) years after initial power up, this unit will chirpevery 30 seconds. This is an operational end of life feature which will indicate that it is time to replace the alarm. UL 2034, the independent standard applicable to CO alarms, requires CO alarms to have an end of life warning. This requirement went into effect in March 2007, meaning any CO alarm manufactured after April 2007 with a UL listing must have this feature. Most states that require CO alarms in residential dwellings mandate that the alarm meet the UL 2034 standard."

Smoke Alarm
"Rechargeable Batteries Save Money, Time, and Labor
The Kidde Silhouette Low-Profile Smoke Alarm features a rechargeable lithium battery sealed inside the unit that recharges automatically via central electricity. If there is a power outage, the battery will recharge once the electricity is restored. Over the span of the alarm's life, this no-fuss unit saves homeowners money, time, and labor on battery changes. For builders, landlords, hoteliers, and apartment managers, this innovative feature cuts down on callbacks, material, and labor costs.

The battery is designed to last the lifetime of the alarm, approximately 10 years. Once the alarm has reached the end of its life, it will chirp every 30 seconds, letting you know it's time for a replacement."

Note the new smoke detectors come with battery backup that lasts the life of the detector, 10 years. The unit is $13.79 so I'd guess it's cheaper to buy a new unit then replace batteries once a year for 10 years.

Ref:
CO Alarm
»www.amazon.com/gp/produc ··· KIKX0DER

Smoke Alarm
»www.amazon.com/Kidde-KN- ··· 5&sr=1-8

That Kiddie alarm looks nice. And awesome that it has a built in battery.

I'm disappointed that it isn't a dual sensor alarm, though.