Kidde smoke and carbon monoxide detector hardwired interconnect combination smoke & co alarm review


What is good n Kidde smoke and carbon monoxide detector? It Test-Hush Feature that silences the unit for approximately 8 minutes; tamper-resistant technology deters removal of the unit from the wall or ceiling. It is a combo smoke and CO detector that operates on a 120V power source with 9V front-loading battery backup. Fire & CO Detector in 1 unit with alert modes, LED lights, & voice alarm, that states, “Fire! Fire!”, “Warning! Carbon Monoxide!”, or “Low Battery!” Know about more benefits in Kidde smoke and carbon monoxide detector hardwired interconnect combination smoke & co alarm review.

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Pros & Cons


  • Very easy to install
  • Has battery backup.
  • Voice alerts
  • Works with other Kidde wall-mount bases
  • Clearly announces if it is a smoke alarm or a CO leak.


  • Batteries need to be changed


  • Part Number: CP9000
  • Model: KN-COPE-D
  • SmokeSensor: Photoelectric
  • Power Source: 9V battery
  • Audio Alarm: 85dB at 10ft
  • CoSensor: Electrochemical
  • Size: 5.79” in diameter x 1.85” depth
  • Temperature Range: 40˚F (4.4˚C) to 100˚F (37.8˚C)
  • Humidity Range: 10%-95% relative humidity, non-condensing
  • Weight: .7lb
  • Interconnects: No

Key features – Kidde smoke and carbon monoxide detector hardwired interconnect combination smoke & co alarm

  • Front-Loading Battery – Speeds up replacement by eliminating the need to remove the unit from the ceiling or wall.
  • Unique Battery Door Design – Will not close if battery is not installed properly.
  • Electrochemical CO sensor – Provides accurate and continual CO protection during the product’s life, remains stable during temperature and humidity changes and resists reactions to household gases that may cause false readings or reduce sensitivity.
  • Photoelectric smoke sensor – May detect visible fire particles associated with slow smoldering fires sooner than an ionization sensor.
  • Voice Warning – Supplements warning from the traditional 85-decibel alarm by clearly stating the danger present, fire or carbon monoxide.
  • Smart Touch Button – One button performs the following functions:
    • Activates the Hush® feature to temporarily silence nuisance alarms (will announce “Hush mode activated,” or “Hush mode cancelled.”)
    • Simultaneously tests the unit’s electronics and verifies proper operation
    • Activates the peak level memory feature (will announce “CO previously detected” if unit has detected levels of 100 ppm or higher)
    • Resets the unit during a CO alarm (Unit will re-enter alarm within 6 minutes of reset if 70ppm or more of CO is present).
    • Silences end of life chirp for two days at a time, up to 30 days maximum.
  • Tamper Resistant – Unit will lock to mounting bracket and battery door will lock to deter theft or tampering.
  • Red LED – Flashes in conjunction with the alarm sounding.
  • Green LED – Will flash every 30 seconds to indicate proper operation.
  • Low Battery Signal – Will chirp every minute and red LED will flash to indicate low battery condition.
  • End of Life Signal – Ten years after initial power, the unit will “chirp” twice every 30 seconds to indicate the need to immediately replace the alarm.

Kidde smoke and carbon monoxide detector hardwired interconnect combination smoke & co alarm review


It is circular shaped with a dimension of 2.64 x 1.85 x 5.79 inches. Fit as direct replacements into the mounting of the old kiddes that simultaneously. Unit came with a 9 volt battery and lights up green when all is good and red when alarm chimes. 

A maximum of 24 Kidde devices can be interconnected in a multiple station arrangement, but cannot exceed the NFPA (National Fire Protection Association) limit of 18 initiation devices, of which 12 can be smoke alarms. With 18 initiating devices (smoke, heat, CO, etc.), interconnected, it is still possible to interconnect 6 strobe lights and or relay modules. 


A red LED will flash & be accompanied by 3 long alarm beeps followed by a verbal warning that warns of fire, carbon monoxide, & low battery. The Hush feature silences the fire alarm for approximately 9 minutes. The green LED on the alarm will flash every 2 seconds when Hush is activated and cancelled. 


This alarm uses a photoelectric sensing technology that detects visible particles associated with smoldering fires sooner than ionization alarms. Ionization alarms detect invisible fire particles associated with flaming fires sooner than photoelectric alarms. Kidde recommends that both types of alarms be installed inside the home to protect against both types of fires.

Using ionization sensor technology, the wired smoke alarm detects invisible fire particles. The combination CO detector provides continuous protection from carbon monoxide, even during power outages. 

LED Indicator

If the green LED is blinking once every 15 seconds, the unit has detected a hazardous CO condition. If the CO sensor has detected a CO level of 100 PPM or higher since last reset, it will be recorded by the Peak Level Memory function. To access the Peak Level Memory press the test/reset button.

Voice alarm

The voice warning feature accompanies the 85dB tone during an alarm event, and helps reduce confusion with verbal announcements such as “Replace alarm” at end of alarm life, and “Hush mode activated” when a nuisance alarm is silenced. The three color LED ring helps users quickly determine standby, alarm, or error mode of the alarm.


I bought a Kidde relay module that actuates a wireless button tied into my Hubitat home automation system. When a fire alarm sounds anywhere in the house, I have it programmed to notify my IPhone, switch on all house lights, and announce the fire on my Echo devices. Works great! The relay module also permits adding a wired commercial “pull station” (like in schools or commercial buildings) to manually sound the fire alarm in all units in the house. 

How to install in Kidde smoke and carbon monoxide detector hardwired interconnect combination smoke & co alarm

I plugged in the three wire (Black, White, Red) connector that went to my old unit into this unit and then added the two AA batteries making sure the red spring tabs in the battery compartment were fitted under each battery. The unit immediately went into test mode. During the initial test, it 1) chirps three long chirps, announces “Fire”, chirps three long chirps…. then…. 2) chirps four quick chirps, announces “Warning – Carbon Monoxide”, chirps four quick chirps…. then…. 3) chirps one last chirp which means testing is done it is now ready to monitor the air in the room. The last thing to do was to mount the unit to the mounting plate that was used for the old KN-COSM-IB unit that was still attached to the ceiling. The whole process took less than 3-4 minutes from unboxing to testing to mounting the unit. 

Alternate of Kidde smoke and carbon monoxide detector hardwired interconnect combination smoke & co alarm

The Nest Protect Smoke and Carbon Monoxide Alarm Is Smart and User-friendly

Power Source: Hardwired or battery | Sensor Type: Photoelectric, ionization, and carbon monoxide | Pack Size: Single

  • Hardwired or battery
  • Multiple alerts
  • Silence false alarms from your phone
  • Comprehensive detectors
  • Expensive
  • Need other smart devices to take advantage of best features

If you’re willing to spend a little more on a smoke detector, the Nest Protect is a top-rated smart smoke and carbon monoxide alarm. This unit comes in both hardwired and battery-powered models, and it connects to your phone via WiFi to send real-time updates on what’s happening in your house.

The Nest Protect includes a variety of useful features beyond smoke and carbon monoxide detection. This smart product automatically tests itself to save you the hassle, and it sends alerts to your phone whenever it detects a problem, letting you know there’s an emergency even when you’re not home. If there’s a false alarm, you can silence the detector from your phone, and when you walk underneath the unit at night, it lights up to help you see better.

Editor’s recommendations

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