Kidde Nighthawk 900-0076

The well-reviewed Kidde 900-0076 carbon monoxide detector is AC operated (meaning you just plug it into a wall outlet), but it has a battery backup that will keep it working during power outages. This unit features a digital display, peak-level memory and test/reset button, but not a low-battery indicator. It's rated highly by experts, who say Kidde Nighthawk stands out for the accuracy of its detectors, and it comes with a five-year warranty. We did read reports from a small percentage of owners about false alarms. If you're good at replacing batteries regularly, you may be better off with the equally well-reviewed, battery-powered Kidde Nighthawk 900-0146 (*est. $40), which allows you to place the unit high on a wall, where carbon monoxide is more likely to be found (since it's a lighter gas than oxygen).

We found the most reliable review of the Kidde 900-0076 carbon monoxide detector at Consumer Reports, which tests and rates numerous CO and smoke detectors. USA Today also recommends the Kidde in a brief article.