See All Carbon Monoxide Detectors


Est. $30
June 2013
by ConsumerSearch

  • CO levels always displayed
  • Flexible placement options
  • Batteries last a year
  • Loud alarm
  • Easy to use
  • Random readings on some units
Where to Buy

Bottom Line

The Kidde KN-COPP-B-LP is an easy-to-use battery-operated carbon monoxide detector that continuously displays CO levels. It is effective, although numerous users complain of getting random peak CO level readings after they reset their devices. The unit lasts seven years (the same length as the limited warranty), and batteries only need replacing about once a year.


Accurate for high CO level readings. Most owners find the Kidde KN-COPP-B-LP to be an effective and easy-to-use carbon monoxide detector that gives no false alerts. Users love its loud horn and the continuous CO displays for levels over 30 parts per million. A peak-level memory displays the highest concentration of carbon monoxide detected since the unit's last reset. But, several people reviewing the device on and complain of having a buggy peak-level button, which could make monitoring a potentially dangerous situation difficult. Some say their units will not show zero even after they reset their detectors, while others report getting random peak level readings under 30 ppm.

For example, one user reports that his unit will change its highest CO level reading whenever he presses the test button. However, he placed his device behind his running car to test its capability for detecting higher CO levels. It rapidly displayed an increase in CO levels and quickly dropped as he moved toward the open door, satisfying him that it was working properly. The detector comes with a seven-year limited warranty, which would cover the faulty units. Kidde customer service was praised by one user who reported the problem and was immediately sent a replacement.

Ease Of Use

Easy to interpret. The detector's display screen makes it easy to monitor CO levels in the house and eliminates much of the guesswork. A green LED light notifies owners that it is operating and a steady zero indicates it has not sensed any carbon monoxide. The display will read "End" when it's time to replace the unit, but the detector also comes with a label so that owners can write in the expected expiration date. Owners love that the battery-operated design means it's free-standing and can be placed on a tabletop or mounted on a wall. The manual recommends placing it at eye level.

The Kidde KN-COPP-B-LP replaces a nearly identical version, the Kidde KN-COPP-B-LS. The new model's sensors last longer (seven years from the point of start-up) than the sensors in the older version (five years). However, some owners lament the new LP version, introduced in late 2011, because it also does away with a continuous backlit display.


Seven-year lifespan. The detector is designed to last seven years from the point of initial power-up. At that time, the unit will beep every 30 seconds to indicate that it has reached the end of its life. The detector takes three AA batteries, which last approximately a year. The unit will flash "LB" and beep every 30 seconds when the batteries need replacing. As with the First Alert CO-400, the Kidde KN-COPP-B-LP's battery cover will not close unless all three batteries are installed first.

Where To Buy
Kidde KN-COPP-B-LS 900-0230 Nighthawk Carbon Monoxide Alarm, Battery Operated with Digital Display

 (69 reviews)
Buy new: $74.99 $36.89   16 Used & new from $19.99

In Stock. Eligible for FREE Super Saver Shipping


Our Sources


About 50 people reviewed the unit on Amazon, with 56 percent giving it a perfect score. Overall, the feedback is positive. Most of the complaints came from owners whose units kept generating error messages or random peak-level readings that would not reset.

Review: Kidde KN-COPP-B-LP 900-0230 Nighthawk Carbon Monoxide Alarm, Battery Operated with Digital Display, Contributors to, As of May 2013


More than a dozen users reviewed the detector on Home Depot's website, giving the unit a 4.8 out of 5 score. Only one person gave it 3 stars (the lowest score) because the unit did not have a constant backlit display.

Review: Kidde Carbon Monoxide Alarm Battery Operated with Digital Display, Contributors to, As of May 2013

Carbon Monoxide Detectors Runners Up:

First Alert Onelink SCO501CN Est. $60

3 picks including:,…

Kidde KN-COPP-B-LP Est. $30

2 picks including:,…

Kidde KN-COPP-3 *Est. $45

1 pick including:,…

Kidde KN-COB-B-LPM Carbon Monoxide Alarm
Buy from
New: $47.07 $15.00   
In Stock.
Average Customer Review:  
Kidde KN-COPP-B-LS 900-0230 Nighthawk Carbon Monoxide Alarm, Battery Operated with Digital Display
Buy from
New: $74.99 $26.95   
In Stock.
Average Customer Review:  
Kidde KN-COPP-3 Nighthawk Plug-In Carbon Monoxide Alarm with Battery Backup and Digital Display
Buy from
New: $69.99 $28.25   
In Stock.
Average Customer Review:  

Back to top