Last Updated on May 6, 2024 by Alarm New England

While most homes on the market today come equipped with fire alarms and carbon monoxide detectors, most homeowners usually forget to test these crucial safety systems to make sure they work.

According to the NFPA, nearly three out of five deaths from home fires come from homes with non-existent or defective fire alarm systems.

Additionally, in 2015, the CDC reported that 393 people in the United States died from carbon monoxide poisoning, with thousands sent to emergency rooms across the country.

What’s shocking about these statistics is that proper maintenance and understanding of these alarm systems could have prevented some of these tragedies. The death rate in home fires is cut by more than half in homes equipped with functional smoke detectors.

The numbers are similar in carbon monoxide-related studies. In a study done in New York City, the NCBI reported a stunning 50% drop in carbon monoxide poisoning cases after New York City enacted a carbon monoxide law requiring CO alarms in dwellings.

Types of Smoke Detectors

The NFPA states that there are two common types of smoke detectors systems, Ionization and Photoelectric.


ionization smoke detector

The first type is Ionization-type smoke detectors. These smoke detectors work by having two plates that each produce either negative or positive ions.

These ions then traverse between the two plates, and this creates a complete circuit. When smoke enters the detector, the path between the two plates become blocked, which is what causes the alarm to trigger.


first alert photoelectric

When smoke enters the detector, the laser, which usually travels in a straight line, becomes disoriented and scatters around the gadget. When this fractured laser hits one of the many light sensors inside of the system, the alarm then triggers.

Which type of smoke detector should I get?

Each type of smoke detector has its advantages. Ionization-type detectors are better at detecting flaming fires, which are fires that produce a lot of flames and less smoke.

Examples of flaming fires are cooking accidents, fires from candles, flammable liquids and burning wood or paper.

candle fire

Photoelectric-type detectors are better at detecting smoldering flames, which are flames that build up over time. These usually come from unattended flammable materials that slowly burn up, such as charcoal and cigarettes.

You will want to put the right type of smoke detector accordingly. In places such as the kitchen, you should probably opt for ionization-type alarms. Areas near the woods, or places where you cook grilled food, might better benefit from photoelectric-type alarms.

carbon monoxide poisoning

Additionally, some alarms come with both types of detection. While they may cost more, you can be sure that those alarms can protect you and your home from both flaming and smoldering fires.

How to Test Your Smoke Detector and How to Maintain It

Testing your smoke detector should become a part of your housekeeping routine and according to FEMA, should be done at least once a month.

While the specific way to test your detector depends on the manufacturer of your smoke detector, most detectors have an easily accessible test button on the face of the device. Once you press this button, wait a few seconds, and then a loud and piercing sound should emit from the device.

qolsys smoke detector ceiling

If you do not hear the device or if the sound is not loud enough, consider replacing the battery and test the device again. If the alarm doesn’t sound off even after you’ve replaced the battery, the device itself is probably faulty. Replace the detector as soon as possible.

Additionally, here are some guidelines you should follow while testing your smoke detectors:

  • Remember to test your smoke detectors monthly as suggested by FEMA. In many cases, this is as simple as just pushing a button.
  • Besides testing the device, clean out your smoke detector as well. Dust, spider webs and other debris may hinder your smoke detector from operating at its maximum capability.
  • You should also replace the batteries at least once a year. Some systems, however, come with a “long-life” battery. These are usually not replaceable, and you may have to replace the smoke detector when the “long-life” battery runs out.
  • Figure out if your smoke detector is a stand-alone or is an interconnected model. A stand-alone model will only trigger itself when it detects smoke, while an interconnected model triggers all the alarms in the system if even one smoke detector goes off. If you live in a large house, consider getting an interconnected system so that your whole residence is made aware of a house fire that may be happening on the opposite side of the house.
  • Station someone at the farthest areas of your house from your smoke alarm. When you test your alarm, they should be able to hear alarms go off. If they don’t, consider using an interconnected smoke detection system or get an alarm with a louder alarm.
  • Some smoke detection systems sold nowadays are also wired to inform your local fire station or home security system when it detects smoke. When testing your smoke alarm systems, notify your fire station so that they don’t send personnel to a non-existent fire. They’ll be thankful for the heads up, and be glad that you’re diligently testing your smoke detection system.
  • Keep an up-to-date escape plan. These smoke detectors only alert you and cannot put out fires for you.
  • Check the dates on the back of your smoke detectors. Once an alarm reaches its 10-year life span, it is advised to replace it entirely. However, you can also consult the alarm’s manual as it may suggest replacing the entire system earlier.

Types of Carbon Monoxide Detector

Like smoke detectors, carbon monoxide detectors come in a variety of mechanisms that detect carbon monoxide levels in the air. System Sensor, a manufacturer of fire protection equipment, lists out the three main types of mechanisms for monitoring carbon monoxide levels.


Biomimetic sensors, as its name implies, mimics the effect of carbon monoxide on hemoglobin. There is a laser in the device that becomes blocked when carbon monoxide levels increase, which then triggers the alarm.

co2 detector

These detectors are usually cheap, although they are more prone to false alarms and take longer to recover once they set off their alarm.

Metal Oxide Semiconductor

Metal Oxide Semiconductor sensors, or MOS, work by heating a semiconductor in intervals. Once it reaches its operating temperature, its resistance changes when carbon monoxide is present. The alarm triggers once the resistance threshold is broken.

carbon monoxide alarm first alert

These alarms have a long life span. However, they also draw more electricity than other variants and are prone to false alarms in the presence of other chemicals or gases.


Within electromechanical sensors, platinum electrode and an acid combine to create a reaction between the air and carbon monoxide, generating an electric current. When these currents pass a certain threshold, the alarm goes off.

electromechanical carbon monoxide alarm

These sensors are highly reliable and react fast to carbon monoxide. They also draw less electricity than other variants. Their only downside is that they may make a false alarm when in the presence of ammonia-based cleaners.

Which type of carbon monoxide detector should I get?

In most cases, the electromechanical sensor is sufficient. However, if you need a carbon monoxide detector in other places such as a workshop, you may want to consider getting a MOS or biomimetic-based detector.

How to Test Your Carbon Monoxide Detector, and How to Maintain It

Like smoke detectors, carbon monoxide detectors ought to be tested regularly. The testing procedure is quite similar:

  1. Press and hold down the test button on the face of the device. After a few seconds, you should hear two beeps which signify that the device has entered testing mode.
  2. If you are unable to hear any sound or if the alarm is too weak, replace the battery and retest.
  3. If after battery replacement the device still doesn’t beep, replace the whole detector as soon as possible.
fire alarm

Guidelines to Test Carbon Monoxide Detectors and CO Alarms

Additionally, here are some guidelines you should follow while testing your carbon monoxide detectors:

  • Like smoke detectors, test carbon monoxide detectors monthly.
  • Clean the carbon monoxide detector thoroughly so that there’s nothing obstructing the entryway to the sensors.
  • While most carbon monoxide detectors are plugged into a wall socket or are hardwired to your house’s electrical system, almost all of them have a backup battery in case of power failure. You should replace your backup batteries once a year.
  • Have an escape plan updated in case the alarm goes off. Carbon monoxide is lighter than air, so it rises. When the alarm goes off, crouch and stay low to the ground while making your way out of the building.
  • Inspect your ventilation systems. Carbon monoxide poisoning happens when there’s a buildup of the gas in an area. Making sure that all the areas in your building are well ventilated. This will drastically reduce the risk of CO alarms and carbon monoxide poisoning.

Must-Have Features for Smoke and Carbon Monoxide Detectors

powerg wireless smoke and heat detector

When looking for which smoke or carbon monoxide detector to purchase, there’s no singular device on the market that will cover all needs. Each household or building has a different layout and rooms with different purposes, which will require different types or numbers of detectors.

It is best to consult with your local fire department and read up on local ordinances to determine what safety standards your state requires.

Keep an eye out on the standards that each device has passed. Manufacturers will state on the packaging or the manual of the device which standards these detectors have passed.

These devices are usually tested by Nationally Recognized Testing Laboratories (NRTL), which are approved by the Occupational Safety and Health Administration (OSHA) to test these products. Major NRTLs include the CSA, FM, INTERTEK, TUV, and UL.

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