- About The Store
- Home Safety FAQs
- View Cart
The First Alert CO400 Carbon Monoxide Alarm utilizes an electrochemical carbon monoxide sensor that lasts for up to five years to detect carbon monoxide. This carbon monoxide detector is battery powered, making it portable and easy to use anywhere, even in the event of a power outage. When carbon monoxide levels become elevated, a loud 85-decibel alarm alerts you to the threat.
The Most Accurate CO Sensor Available
The First Alert Carbon Monoxide Alarm uses an advanced electrochemical CO sensor to detect elevated carbon monoxide levels. When CO is detected, the carbon monoxide detector sounds an alarm to warn you of the threat.
Comprehensive Warning Features
When carbon monoxide levels rise, the carbon monoxide detector sounds an 85-decibel siren that is designed to wake even the soundest of sleepers. A low-battery light and alarm alert you when battery power is running low, and an end-of-life timer lets you know when the device should be replaced. Each CO detector lasts approximately five years.
Simple and Easy to Use
The First Alert Carbon Monoxide Alarm is easy to set up. Simply insert the battery, and the CO detector will start to monitor your space for carbon monoxide. There are no complicated displays or settings to navigate–a single button silences the alarm and tests the CO detector. A pull-down action chart instructs you of what to do if the CO alarm goes off.
Where To Place Carbon Monoxide Alarms: One on every level of the home and one in each sleeping area.
First Alert Carbon Monoxide Alarm CO400
Average Customer Rating Based on 123 reviews:
Easy to Use - 11/12/2018
Reviewer: SHIRLEY WHITNEY
Simplicity is rare. The alarm tested loudly and fits on one existing screw from an earlier alarm. As the screws are a little further apart, the other side rests on my smoke alarm.
correct - 10/04/2018
Reviewer: Charles Curtis
Received product in a timely manner. Will not use this product until next summer as it will be placed in our camper, replacing the old one that went bad on our last camping trip. Thank you.
Great Carbon Monoxide Detectors - 09/25/2018
Reviewer: New Canaan Fire Department
If a resident of our community needs a Carbon Monoxide Detector these are the detectors we hand out. The low cost and great product allows us to give out more detectors and give the community the protection they need.
Reviewer: Abraham Butensky
very easy to use and inexpensive.
Overview - 07/24/2018
Reviewer: Marinela Cyriacks
The product works great and is easy to install.
CO Monitor - 06/13/2018
Reviewer: Joyce Rudick
Excellent size and easy to install.
Home Essential - 06/07/2018
CO detector to help keep your family safe from the odorless, colorless and potentially lethal carbon monoxide gas.
First Alert Battery Operated CO Alarm - 05/25/2018
Reviewer: Patrick Chu
Ordering the CO monitor directly from First Alert online was easy, and product actually arrived earlier than the estimated date! Installation is simple and quick. Besides being price competitive, you can't beat free shipping. The extra nice touch is they even include the 9V battery! Next time needing to buy First Alert product, go to their website, and forget about hunting around at stores or other websites.
Very good - 04/25/2018
Reviewer: Meli Ramirez
Very good prices and great product!
first alert basic CO400 - 04/23/2018
Reviewer: Jacqueline Agresta
Have always used in the past and found to be very good.
Actual battery service life depends on the particular design of your smoke or carbon monoxide alarm and the environment in which it is installed. All kinds of alarm batteries specified in the user's manual are acceptable replacement batteries. Regardless of the manufacturer's suggested battery life, you MUST replace the batteries immediately once the unit starts "chirping" (the "low battery warning"). It is recommended that you change the batteries in your alarms when you change your clocks for daylight saving time. Also consider replacing your current alarms with 10-Year Life Alarms that never require a costly battery replacement for the ten year life of the alarm. This 10-Year series is available in smoke, carbon monoxide and combination alarms.
We make it as easy as possible to ensure you get the lowest prices available: