Best Smoke Detector 2020: Ionization, Photoelectric, Dual Sensor?


When it comes to making sure that your house is safe from smoke or fire, you should choose only the best smoke detector. To do this, you need to know about the types of smoke alarms, factors to consider when choosing one, and how many smoke detectors you need. This article gives all of these information so that you can make a wise decision.

Moreover, it also helps to know about the different kinds of smoke alarms available in the market. You’d be surprised to know that there are alarms that double as a carbon monoxide detector. There are also alarms that are designed for the hearing impaired. Read on to find more about the best smoke detectors for homes out there.

Best Smoke Detector I

Types of Smoke Detectors And Alarms

In order to choose the best quality smoke detectors that you need, you should know about the different kinds of alarm systems first. Basically, there are two major kinds of alarm systems: the heat detector and the smoke alarm. It is important to know the differences between them.

  • Heat Detectors

The earliest form of fire alarm is the heat detector. As the term suggests, it is able to “detect” an increase in temperature in a room or space. Once the temperature reaches a specific level, the heat detector sends a signal to alert people about the occurrence of fire.

Heat detectors are most suitable for places where high-temperature fires are most likely to happen. These work best in places where the speed of heat detection is not a major consideration. Moreover, these are often used in places where heat detectors are preferred over smoke alarms.

For most homes, residential smoke alarms are usually favored over heat detectors. This is because smoke alarms are faster than heat detectors when it comes to detecting the presence of fire. And so, smoke alarms are considered as more effective in this case.

  • Smoke Alarm
  • Ionization

This kind of smoke alarm is best for detecting a rapid and raging fire. It contains a very small amount of radiation, which goes through a space in the middle of two electrodes. This space is called the ionization chamber, where there is a constant current passing between the two electrodes.

  • Photoelectric

This kind of fire alarm is suitable for slow-burning fires. It involves the use of a source of light, a collimating system with a light beam, and a photoelectric sensor. When smoke from a fire reaches its chamber, it crosses paths with the light beam. The smoke causes some light to scatter and reach the photoelectric sensor, which sounds of the alarm.

Once smoke from a fire reaches the chamber, it absorbs alpha particles. The reaction causes a reduction in the ionization process as well as an interruption in the passage of the current. All of these changes trigger the fire alarm.

  • Combined Ionization and Photoelectric

For best results, some people opt to use an ionization smoke alarm together with a photoelectric smoke alarm. This way, all kinds of fires can be detected, including smoldering and flaming fires. It is possible to install both kinds of home smoke detectors in a single place

Aside from the kind of fire alarm, you should also be familiar with different power sources. For example, there are smoke alarms that are powered by 9-volt batteries. These are not expensive, making them a popular choice among users. But their batteries should be replaced regularly.

In contrast, there are smoke detectors for homes that are powered by 120-volt lithium batteries. These power sources can last for up to 10 years and are most suitable for larger homes and apartment buildings. It also allows the interconnection of multiple smoke alarms together in one place. Some even feature a strobe light, which is designed specifically for the hearing impaired.

Regardless of the type of detector or power source, you should be ready to maintain and replace your devices regularly. For best results, conduct a detector test every month to ensure that it works. What’s more, consider changing the batteries at least once a year. This way, you can prolong the life of your value smoke detectors.

How To Choose A Smoke Detector

Once a fire starts, it could spread very quickly, giving you only two minutes or less to evacuate your house. But if you have installed the right kind of smoke detector, your chances for evacuation and survival increases. And so, you should learn how to select the best residential smoke alarms for your home. Here are some of the things that you need to consider.

  • Type of Smoke Detector

As cited earlier, there are different types of smoke detectors, each of which has its own strengths and weaknesses. These types include ionization smoke alarms, photoelectric smoke alarms, and dual-sensor smoke alarms.

The first type of smoke alarm “ionizes” the air using a small amount of americium 24, which is a radioactive material. The process sets up an electric current, which gets disrupted the moment smoke comes in. This triggers the alarm, which comes in handy in detecting fires that occur rapidly. These include fires that involve paper, grease, and most arson cases. Notably, some of these alarms are fitted with carbon monoxide detectors.

The second type, photoelectric smoke alarms, feature a tiny, pulsating light. As soon as smoke enters its chamber, this light scatters and reaches a sensor, triggering the alarm. This type of alarm is more suitable for the detection of flaming fires, including those involving electricity, clothes, bedding, and furniture. They are more expensive than ionization smoke alarms, but they are less likely to be triggered by accident.

The third type of smoke alarm is actually a combination of photoelectric and ionization alarms. They can be installed as separate units or integrated into a single device. In any case, having both types enables you to detect both fast-burning and slow-burning fires. This option may cost more but it provides a greater amount of safety for your home.

  • Power Source

As mentioned previously, you should also consider the power source of your smoke detector. Most smoke alarms operate on 9-volt batteries, such as AA and AAA batteries. Your should replace these batteries regularly, at least once a year.

On the other hand, some of the best smoke alarms operate on lithium batteries, which can last for up to 10 years. Still, there are smoke alarms that you can plug into electric outlets. These often come with back-up batteries, which you can use in case of a power outage.

  • House Size

The size of your house also plays a role in the selection of smoke alarms. Ideally, there should be one alarm for every room, including your attic and basement. Smoke alarms should also be installed in every hallway, in between the rooms.

If your house is huge and you need several smoke alarms, consider wiring them together. This way, when one alarm sounds, the others do the same. Even if you and your family are in separate rooms, you will hear the alarm at the same time and evacuate with safety.

Moreover, when installing a smoke alarm in the kitchen, look for a photoelectric alarm instead of an ionization alarm. The latter is more sensitive and could go off even when you are just cooking. You would not want to be bombarded by false alarms every time you use the kitchen stove!

  • Certification

Regardless of the type of smoke detector that you buy, make sure that it has proper certification. Look for a sign or logo indicating that the unit has been tested and certified by an authority, such as Underwriters Laboratories, Inc. Aside from initial testing and certification, these laboratories also hold follow-up tests to make sure that alarm manufacturers follow their standards.

  • Testing

Before you buy a smoke detector, ask the seller first if there is a way to test it. This way, you can test your smoke alarm every month to see if it is working. There are smoke alarms that include a “test” button that makes it easy for you to check. You can also look for alarms that come with a remote control so that you do not have to climb up a ladder just to check every time.

  • Maintenance

Choose a smoke alarm that is easy to clean and maintain. For instance, there are models that come with a removable cover, which you can take off whenever you need to clean them. If you do not vacuum your smoke alarm at least once a month, the dust could accumulate on the sensors. Over time, this could lead to annoying false alarms.

  • False Alarms

Speaking of false alarms, our automatic response would be to turn them off as soon as possible. This means that you should look for a smoke alarm that you can turn off easily without having to disable the whole unit. Otherwise, you will need to remove the batteries altogether and have to put them back in every time there is a false alarm.

  • Special Features

Do you or anyone in your family have special needs? If so, you might want to consider buying a smoke detector that suits your needs. For example, there products that are designed for the hearing-impaired. Aside from the sound alarm, these include a visual signal so that everyone can be alerted when it goes off.

How Many Smoke Detectors Do You Need?

If you are wondering how many smoke detectors you need, check the number and location of bedrooms in your house. This is important, because even if everyone is sleeping, you would want them to be woken up as soon as the alarm goes off. You do not have to put them in the bedrooms themselves, but rather in the hallways in between rooms. Make sure that they can be heard in every bedroom in the house.

If your bedrooms are located on different floors, make sure that there is a electric smoke detector on each floor. In any case, you can always ask your building inspector for tips on setting up smoke detectors. You may also get in touch with your local fire department for more information about the best home smoke detectors and their possible locations.

Top 10 Best Smoke Detectors

To help you choose a smoke detector that fits your household needs, here are 10 of the best rated smoke detectors available.

Kidde i4618 (Firex) Hardwired Smoke Alarm with Battery Backup

This product comes with a False Alarm control, which you can use to silence a false alarm for up to 15 minutes. It is powered by 120v AC as well as a 9 volt battery for smoke detector in case of power outage. You can also connect it to a maximum of 18 devices, including 11 other Firex smoke alarms plus six Firex heat alarms. This may be the best hardwired smoke detector that you need.

The Kidde i4618 (Firex) has a tamper-resistant feature to keep the unit protected. It also has a “battery missing” reminder, since you cannot attach it to the mounting base when there is no battery inside. Furthermore, when the battery is weak or when the unit is not properly connected, it will emit a short beep to alert you.

The smart smoke alarm features green LED light when it receives power or is working normally. In contrast, it shows a red LED light when there indicating a fire alarm and a false alarm. It emits a loud horn sound at 85 decibels, which alerts everyone in the house during an emergency. Meanwhile, you can use the test button to check the unit from time to time.


  • Includes a power link tab for fast and easy installation
  • Features a low battery indicator and a front loading door for easy battery change
  • Red LED light alerts even the hearing-impaired during an emergency


  • The unit is sensitive to smoke and steam, such as those emitted by cooking or a hot shower. You might hear false alarms every now and then
  • You might need to use a new mounting bracket, as the product dimensions could be different from the units that you already have

First Alert SA320CN Dual Sensor Battery-Powered Smoke and Fire Alarm

This product contains both photoelectric and ionization sensors, making it possible to detect flaming and smoldering fires. The photoelectric feature enables the alarm to detect flaming fires, such as clothes or bedding ignited by a lit cigarette. Meanwhile, the ionization feature can easily detect fast-burning fires, such as grease fires in the kitchen. In fact, this product is one of the best ionization and photoelectric smoke alarms in the market.

Having both kinds of sensors, the First Alert SA320CN Dual Sensor Battery-Powered Smoke and Fire Alarm is useful for any home. As a battery operated smoke detector, it comes with two AA batteries that are included in the package. There is a battery door that you can access easily, so you don’t have to remove the unit from the ceiling whenever you need to replace the battery. More importantly, the unit emits a loud, 85-decibel sound that everyone in the room can hear in cases of emergency.


  • Has ionization and photoelectric sensors for detecting all kinds of fires
  • Uses intelligent sensing technology
  • Comes with a 10-year warranty


  • Very sensitive to smoke. Do not place it in the kitchen as the smoke from cooking could trigger false alarms
  • The “test / silence” button lasts for only 10-20 seconds, so you will need to press it again. This period is short, so you might feel tempted to take out the batteries
  • When installed inside a closed room, the alarm might not be loud enough for people outside to hear. It is best to install it in the hallway so more people would hear it

Kidde Model KN-COSM-BA with Voice Warning

This product offers a two-fold function: smoke detection and carbon monoxide detection, which comes in handy as this gas is dangerous for your health. In other words, this could be the best dual sensor smoke alarm in the market. The alarm has a unique voice warning system that “announces” the presence of fire or carbon monoxide. The voice also alerts people when the battery is low or when the “hush” feature is activated. The voice system makes it different from most other cigarette smoke detector, which often emit horn or ringing sounds.

You can use the Kidde KN-COSM-BA with Voice Warning even when there is a power outage. You just need to put three AA batteries to keep the unit running. It includes ionization sensors for detecting fast-burning fires as well as as photoelectric sensors for detecting slow-burning flames. This combination of ionization and photoelectric sensing can help you detect different kinds of fires. Moreover, the product is easy to install and you do not need to set up wires around your home. If there is a false alarm, simply press the “hush” button to silence the unit.


  • Unique voice system that announces “Fire!” or “Carbon monoxide!”
  • Features a “hush” button for silencing false alarms
  • Separate smoke detector test button for regular checking and maintenance


  • Compared to the audio alarm of most detectors, the voice alarm of this product may not be loud and hard enough to alert everyone in the house
  • Uses batteries quickly, may need replacement every month

Nest Protect Smoke Plus Carbon Monoxide, Wired 120V S2001LW

The Nest Protect is a smoke alarm and carbon monoxide detector in one. Carbon monoxide is an invisible, odorless, and poisonous gas, so you wouldn’t want it to accumulate in your house. Fortunately, you can configure the product to send a message to your phone during an emergency. This way, you can be alerted even if you are not inside your home or office. Moreover, the WiFi smoke detector can notify you when battery levels are low and need to be replaced. Before you go to sleep, check to see if it emits a green light. This means that the power is “active,” so you won’t be waking up to false alarms during the night.

As soon as it detects fire or carbon monoxide, the Nest Protect Smoke Plus Carbon Monoxide sounds an alarm. This is followed by a voice alert that tells you whether it detected fire or carbon monoxide. The product is also very easy to install. Just a few minutes and you’re done! What’s more, connecting it to your phone, tablet, and other devices is easy. This just might be the best smoke and carbon monoxide detector out there!


  • Sends a message directly to your phone when there’s an emergency
  • Voice alerts you to the presence of fire or carbon monoxide
  • Low-battery alert to remind you when the batteries need changing


  • Unit is smoke-sensitive and gives off false alarms when detecting cooking smoke or steam from a hot shower
  • Requires regular cleaning and maintenance. Otherwise, dust will accumulate on the sensors and cause false alarms

First Alert BRK SC-9120B Hardwire Combination Smoke / Carbon Monoxide Alarm

This product stands out for its dual purpose of detecting smoke as well as carbon monoxide, which is a deadly, odorless gas. If you have a fireplace, gas furnace, water heater, and other similar devices, the carbon monoxide they emit could reach dangerous levels. Fortunately, the product can help you detect the presence of this deadly gas.

The First Alert BRK SC-9120B can be connected with up to 18 units (12 other alarms, six bells, horns, and other devices). They can all be connected in such a way that when one alarm is triggered, the others will sound off, too. The unit is one of the best interconnected smoke detectors out there. Meanwhile, you can test the product using the test / silence button.

This product also includes a 9-volt battery, which you can use as backup whenever there are power outages. It also has indicator lights for power and alarm, as well as a “chirp” sound when the battery gets low. Moreover, it is UL-certified and meets the standards for carbon monoxide and smoke detector.


  • Dual purpose; detects smoke and carbon monoxide
  • Comes with a 7-year warranty
  • Tested by Underwriters Laboratories, Inc


  • Requires monthly cleaning, otherwise the sensors will accumulate dust, which could lead to false alarms. However, it can be a hassle to clean if installed in high ceilings
  • If you had used an older alarm, you may need to install new wires and connections because the measurements are not same

First Alert BRK 9120B Hardwired Smoke Detector

This product is part of an upgraded series that are easier to install and perform better than older models. In fact, this could be the best 10 year smoke detector that you need. It is an ionization smoke alarm that can detect smoldering fires. It can be connected with up to 18 devices, including 12 other smoke alarms, plus six horns, repeaters, bells, and other devices. This means that when one alarm sounds, all the others will go off as well. The product comes with an alarm indicator so you can easily identify which device went off first. This makes it one of the best wired smoke detectors in the market today.

The First Alert BRK 9120B Smoke Alarm with Battery Backup, Single can be plugged into an electric outlet. However, it also comes with a 9-volt backup battery in case of power outage. Furthermore, you can test it from time to time using the test / silence button. Maintaining it is easy as there is dust cover to keep the alarm clean. The product also includes a user’s manual that people can refer to whenever they need instructions.


  • Comes with a 10-year warranty
  • Certified by Underwriters Laboratories, Inc
  • Easy to set up and maintain


  • Does not include different adapters, but contains a “power connector” where you can connect black, orange, and white wires
  • If you used an older model, you will need to use a new mounting ring. This is because the dimensions of old and newer models are not exactly the same

First Alert SCO5CN Combination Smoke and Carbon Monoxide Alarm

This product doubles as a smoke alarm and carbon monoxide detector. Considering that carbon monoxide poisoning cases are on the rise, this product can help you keep your family safe. It can detect the presence of this deadly gas, even if you cannot see or smell it. So if you are looking for something that can warn you when there is fire or carbon monoxide, this is the product you need. Indeed, this could be the best battery operated smoke detector that you are looking for.

The First Alert SCO5CN contains an electro chemical carbon monoxide sensor and a photoelectric smoke sensor. Once triggered, it emits a loud sound that even elderly people can hear. There are unique sounds for carbon monoxide and smoke detection, so you can tell the difference. It also comes with Optipath 360 Technology, which can detect smoke quickly. Meanwhile, the silence / test button enables you to switch off false alarms and conduct regular testing. You can mount the alarm on your walls or on the ceiling, whichever way you prefer


  • Dual purpose; detects carbon monoxide and smoke
  • Comes with a 5-year warranty
  • Tested and certified by Underwriters Laboratories, Inc
  • Smart auto sensor adjusts fan speed according to air quality


  • The product is really smoke-sensitive. Shower steam and smoke from cooking could set of the alarm repeatedly. If this happens, do not be tempted to just take out the batteries; use the silence / test button instead
  • Requires regular vacuuming every month or so. Otherwise, the sensors gather dust and get triggered more easily even without a fire

Kidde i9040 Ionization Sensor Smoke Detector

This is a battery-operated smoke alarm that you can use even during a power outage. With a diameter of only four inches, it is smaller and lighter than most smoke alarms. If you live in a house that has limited space, this could be the one you need. Likewise, if you are looking for a small smoke alarm that will blend in with the furniture, this unit is a possible choice.

You can install the Kidde i9040 even without wires. It also features a test button that enables you to check the unit regularly, including the horn, circuit, and batteries. Once the power reaches low levels, you will hear a “chirp” sound that reminds you to change the battery.

The product uses ionization sensors to recognize fast-burning fires as well as photoelectric sensors, which are great for detecting slow-burning fires. Both types of sensors are recommended for detecting different types of fires that could occur in your home.


  • Four-inch diameter; smaller and lighter than most other smart smoke detectors
  • Easy to install and maintain
  • Comes with a three-year warranty
  • Tested and approved by Underwriters Laboratories, Inc.


  • The product is really smoke-sensitive, so you might want to keep it away from kitchen smoke and hot steam showers. Otherwise, it will emit false alarms constantly.
  • The unit uses batteries rapidly, so you might need to replace the batteries every four weeks or so.

Kidde KN-COSM-XTR-BA Nighthawk with Voice Warning and Intelligent Alarm Technology

This product can detect slow-burning fires through its photoelectric sensors, as well as fast-burning flames through its ionization sensors. Furthermore, it can also detect the presence of carbon monoxide, which is a deadly and poisonous gas. This ability to detect different kinds of fire along with carbon monoxide gas makes this smoke and carbon monoxide alarm ideal for everyone.

When the Kidde KN-COSM-XTR-BA Nighthawk Battery Operated Combination Smoke / Carbon Monoxide Alarm with Voice Warning, Intelligent Alarm Technology detects fire, it emits a red light and three long beeps. This is followed by a voice shouting, “Fire!” Meanwhile, when the product detects carbon monoxide, it emits four short beeps and then a voice shouting, “Warning! Carbon monoxide!” It can also distinguish between a real fire and a false one.

This 10 year smoke detector also comes with a “hush” button to silence false alarms and a test / reset button. It can run on two AA batteries and sounds an alert when battery levels are low.


  • Features Optipath 360 Technology, making it easier to detect smoke anywhere
  • Comes with a 10-year warranty
  • Tested and approved by Underwriters Laboratories, Inc


  • Product is sensitive to smoke, so smoke from cooking or steam from a hot shower could trigger the alarm easily
  • You will need a new mounting base to set it up, as the measurements could be different from your previous smoke alarm
  • It is slightly bigger than other detectors at 6.6 x 10 x 10 inches. Not the best choice if you are looking for a smaller model

First Alert SA710B Photoelectric Smoke Alarm

This is a photoelectric smoke alarm that uses light beams to detect smoke and trigger an alarm in case of fire. It is environment-friendly and useful for detecting slow-burning fires. It has the best 9 volt battery for smoke detector that you can use whenever there is a power outage. The product contains a battery drawer on the side, which makes it easier for you to replace batteries. It also has an alert that reminds you when the battery level is low and needs to be changed. This may be the best photoelectric smoke detector that you can find out there.

The First Alert SA710B Photoelectric Smoke Alarm with 9-volt Battery also comes with a silence / test button. You can use this to turn of a false alarm as well as to test the product from time to time. You can also use an optional pin, which locks the unit in place and keeps it safe from being tampered. You can mount in on the wall or ceiling and set it up even in mobile homes.


  • Requires little to no maintenance for long-time since it does not make use of filters
  • Presence of ozone can be felt after some time of run
  • Wide area of coverage for operation
  • The fan is strong and the heat sinks work well


  • It Can only be operated in some unoccupied closed spaces
  • It's too loud after 40,000 hours of usage

Before you buy a smoke detector, consider your particular situation first. What kind of fire protection are you looking for? Are you worried about fire, or do you want to be safe from carbon monoxide as well? Do you want an interconnected system of smoke detectors or do you want battery operated ones that you can place anywhere? By answering these questions and figuring out your specific needs, you can choose the best fire and smoke detectors for your family.