5 Best Portable Carbon Monoxide Detectors of 2025, Lab-Tested by CR Experts

Currently, only 14 states require CO detectors in hotels, motels, and rental units. This patchwork of safety regulations led to more than 900 CO-related injuries and nearly two dozen preventable deaths at U.S. hotels, motels, and resorts between 2005 and 2018. And so it would help to have additional protections—such as those provided by the proposed Safe Stay Act, federal legislation endorsed by CR that would require CO detectors in all short-term rental rooms across the country.

Unlike natural gas, which has a distinct odor when it leaks from your stove, carbon monoxide is colorless and odorless and can cause illness or death within hours of exposure. Adding to the risk, the earliest signs of CO poisoning—headache, dizziness, and nausea—are easily mistaken for a common cold or a migraine, making CO detectors that are properly installed and maintained crucial to family safety.

As noted above, some portable CO detectors performed poorly in our labs, taking too long to sound an alarm or reporting inaccurate CO levels.

The X-Sense Portable Carbon Monoxide Detector XC01-R earned the lowest score in the group. It took 19 minutes to send an alarm when exposed to 400 ppm of CO, a level that can be life-threatening within just a few hours. It’s the only model in our ratings to fail this specific test. It also displayed inaccurate CO levels.

The Aotiqual Portable Carbon Monoxide Detector SN-CO305 performed nearly as poorly. While it quickly detected a 400 ppm level, it took more than 4 hours to alarm when exposed to 100 ppm of carbon monoxide. It also gave inaccurate readings of the current CO levels. 

Other models that failed to earn CR’s recommendation include the X-Sense Portable Smart Carbon Monoxide Detector and the TopTes Carbon Monoxide Detector CT-300. Both sounded an alarm when exposed to CO in our labs, but we rated the accuracy of the CO level readout as poor for each option in at least one test.

To keep you safe, a portable CO detector needs to alert you quickly when CO levels are high. To test speed and reliability, our testers place each device in a closed chamber with a certified concentration of carbon monoxide (100 and 400 ppm) and record the time at which each one sets off the alarm. The best models sound off quickly during both tests. 

All the models we test report the specific CO level—either on a built-in display or via a voice message—and we check to see whether this data is accurate. In our labs, we expose detectors to a range of CO levels (30, 100, and 400 ppm) within the closed chamber. The highest performers report CO amounts very close to the actual levels across all of the tests. The models that receive midrange scores slightly underreport the amount of exposure, while models that receive poor scores significantly underreport the amount or fail to display a CO level at all. 

Some devices offer additional features that may be important to shoppers, like a long-lasting battery or real-time temperature and humidity readings. CR doesn’t test device performance outside of carbon monoxide detection and reading accuracy, and so these features aren’t incorporated into the Overall Scores. 

For more information on how to properly install carbon monoxide detectors in your home and keep you and your family safe, refer to our buying guide and full CO detector ratings. Both are available to all readers, free of charge.