First Alert Smoke Alarm with Smart Sensing Technology and Nuisance Resistance - SA320CN (1039828)

  • First Alert Smoke Alarm with Smart Sensing Technology and Nuisance Resistance - SA320CN (1039828)
  • First Alert Smoke Alarm with Smart Sensing Technology and Nuisance Resistance - SA320CN (1039828)
  • First Alert Smoke Alarm with Smart Sensing Technology and Nuisance Resistance - SA320CN (1039828)
  • First Alert Smoke Alarm with Smart Sensing Technology and Nuisance Resistance - SA320CN (1039828)
  • First Alert Smoke Alarm with Smart Sensing Technology and Nuisance Resistance - SA320CN (1039828)
Dual Sensing Battery Operated Smoke Detector
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Smoke Alarm w/ Smart Sensing Technology and Nuisance Resistance

The First Alert SA320CN Dual-Sensor Smoke and Fire Alarm provides early warning of both flaming and smoldering fires. Additionally, its intelligent sensing technology is designed to cut down on nuisance alarms from cooking smoke or other common false-alarm triggers. A single button both silences and tests the smoke detector for simple operation. The battery-powered fire detector can be easily installed anywhere without wires.

Dual Sensors Detect Different Types of Fires

The First Alert Smoke and Fire Alarm comes equipped with two different sensors to offer the earliest possible warning of a fire. The ionization sensor detects flaming fires, such as grease fires or wastebasket fires, and the photoelectric sensor detects smoldering fires, such as when a lit cigarette ignites clothing or upholstery. Both sensors work together to provide comprehensive smoke and fire detection.

Smart Sensor Minimizes False Alarms

People sometimes disable a fire detector when it goes off due to cooking smoke or steam, even though in doing so they endanger themselves and their loved ones. Intelligent sensing technology in the First Alert Dual-Sensor Smoke and Fire Alarm is designed to distinguish between real fires and nuisances, reducing false alarms significantly so there is never a need to disable the alarm.

Battery-Powered Fire Detector Installs Anywhere

The battery-powered fire detector can be installed anywhere with no wires or electrician required. A low-battery indicator light and audible chirp let you know it is time to change batteries. The battery compartment opens without the need to remove the alarm from the mounting bracket, making battery replacements quick and easy.

First Alert Smart Sensing Smoke Alarm SA320CN

* California and New York Residents - Please note this alarm is not compliant with your state's 10 Year Sealed Battery Alarm Legislation Requirements.

Smoke Alarm w/ Smart Sensing Technology and Nuisance Resistance Features:

  • Dual smoke sensors, dual photoelectric and ionization smoke sensing technologies for optimal sensing of smoke particles produced in both flaming and smoldering fires.
  • Smart sensor, helps recognize the difference between non-threatening conditions and real emergencies.
  • Mute button, mutes unnecessary alarms immediately. Also tests alarm function with same button.
  • EZ access battery door, no need to remove alarm from ceiling to change battery.
  • Two AA batteries included.
  • Loud 85db alarm.
  • 10-year limited warranty, smoke alarms should be replaced every 10 years for maximum protection.
  • Meets UL217 standard for dual sensor home smoke detectors.
  • Emits T3 Pattern.
  • Product Dimensions (LxWxH): 5 x 5 x 2 in.
  • Product Weight: .9 lbs.
Product Specs

Ionization smoke alarms are designed to identify fires that are defined by their rapid flaming qualities. These fires are characterized by their ability to generate and combust at an advanced speed (ie. kitchen grease fires or fires fueled by paper burning in a wastebasket).

Photoelectric smoke alarms specialize in detecting fires that are indicative of their slow smoldering properties. These fires are defined by their propensity to produce large smoke particles that can smolder for hours before bursting into larger flames (ie. those caused by cigarettes or candles burning on couches or bedding).

For maximum protection and full coverage from all types of fires, your best option is to use a smoke alarm that features both photoelectric and ionization sensing technologies.

Write A Customer Review Review


Average score based on 74 reviews

Rating: 4.93243243243243/5Rating: 4.93243243243243/5Rating: 4.93243243243243/5Rating: 4.93243243243243/5Rating: 4.93243243243243/5

Rating: 5/5Rating: 5/5Rating: 5/5Rating: 5/5Rating: 5/5Very pleased

Reviewed: 07/17/2019 by Steven Senart

Ordered 8 dual sensor units to replace 10 year old first alert Ionization smoke detectors. Reviews on other sites claimed the ionization only units were of lower quality than in the past while the dual sensor alarms got good reviews. Decided to buy from the First Alert Store to make sure I received genuine First Alert products rather than fakes as some reviews on Amazon were claiming they did not get genuine product from a different seller. Also I was able to get a 30 day return while the Amazon seller did not offer any return. I called and was assured that product would not be years old when received. Ordered in July 2019 and product received was dated December 2018 compared to reviews on Amazon claiming 3 year old product being shipped from that seller. This is important as you can not see the date until you cut open the plastic package and the 10 year unit life goes from the date on the unit. Also bought without the 10 year sealed battery as reviews on other sites claimed the batteries did not last 10 years and in some cases only a couple years at which point the unit with the sealed battery is useless. Price was competitive with other sites. Will buy from First Alert store again in future. So far no problems false alerts with detectors near bathroom or Kitchen but units have only been installed for a week. For 5 of the units I was able to reuse the old already installed mounting brackets/rings which was nice. For 3 others I had to use the new brackets but the screw holes lined up with the old screws so I did not have to drill new holes as mounting brackets have multiple hole options.

Rating: 5/5Rating: 5/5Rating: 5/5Rating: 5/5Rating: 5/5SA320CN

Reviewed: 05/13/2019 by Ben Perkins

Great reviews main reason purchased, all set for another 10 years

Rating: 5/5Rating: 5/5Rating: 5/5Rating: 5/5Rating: 5/5First Alert Smoke Alarm

Reviewed: 05/08/2019 by Maryann M

Installed very easy. Waiting to see if it works, hopefully don't need it for anything that bad.

Rating: 5/5Rating: 5/5Rating: 5/5Rating: 5/5Rating: 5/5MULTI-PROTECTION

Reviewed: 04/12/2019 by Douglas Kantner


Rating: 5/5Rating: 5/5Rating: 5/5Rating: 5/5Rating: 5/5Nice alarm

Reviewed: 04/12/2019 by Milton Yamamoto

This is my second unit. I was very pleased with the first one so ordered another for the living room.

Rating: 4/5Rating: 4/5Rating: 4/5Rating: 4/5Rating: 4/5

Reviewed: 03/26/2019 by SB

A bit thick, but seems ok.

Rating: 5/5Rating: 5/5Rating: 5/5Rating: 5/5Rating: 5/5Worth the wait

Reviewed: 03/25/2019 by Milton Yamamoto

The alarm took a while to get here I live in Hawaii but once I received it I was very happy. Love the AA bakery and compartment. The 9v battery with my old unit was a real pain! Also the Smart Sensing worked well. It didn't go off while cooking like my old one always did!

Rating: 4/5Rating: 4/5Rating: 4/5Rating: 4/5Rating: 4/5some people might not know what Nuisance Resistance means

Reviewed: 03/11/2019 by Pamela Paschall

This product is also rated very well with Consumers and I chose it for that reason as well as I did not see any recalls for it. It is too soon for me to know how well it works in our home as just installed so my number is based on information researched.

Rating: 5/5Rating: 5/5Rating: 5/5Rating: 5/5Rating: 5/5Easy installation

Reviewed: 02/22/2019 by Chris Beall

I ordered 2 of these units and they arrived yesterday. I had both of them installed replacing ancient ones in about an hour. The instructions were clear. Note that once you open the battery compartment you won't be able to close it completely until you have installed the batteries, a safety feature. Both units tested OK. In the 20 hours since they were installed, they have done nothing good except blink an almost-invisible green light about once a minute also good, cause it confirms the batteries are OK. I can provide a more thorough review in a year or so.

Rating: 5/5Rating: 5/5Rating: 5/5Rating: 5/5Rating: 5/5Dual Sensor Smoke detectors

Reviewed: 02/11/2019 by eli klugmann

These types of detectors sense both types of fires, slow smoldering, and fast burning. These are the only ones to buy! And fast service, good price.

Rating: 5/5Rating: 5/5Rating: 5/5Rating: 5/5Rating: 5/5Repaced 10-yr old alarms

Reviewed: 02/04/2019 by Dennis Martin

I needed 6 dual sensor alarms to replace expired alarms. Very good price and fast delivery direct from First Alert. Very satisfied with purchase.

Rating: 5/5Rating: 5/5Rating: 5/5Rating: 5/5Rating: 5/5

Reviewed: 01/28/2019 by Billy Warhurst

great product and fast shipping.

Rating: 5/5Rating: 5/5Rating: 5/5Rating: 5/5Rating: 5/51st Alert Smoke Alarm

Reviewed: 01/16/2019 by Dana Dangar

So far, easy to install in the home, comes with batteries and works as advertised. Good deal.

Rating: 5/5Rating: 5/5Rating: 5/5Rating: 5/5Rating: 5/5

Reviewed: 01/16/2019 by Christopher Paul

Great value and reviews and comes with battery.

Rating: 5/5Rating: 5/5Rating: 5/5Rating: 5/5Rating: 5/5Dual is wise.

Reviewed: 01/07/2019 by Van Sikes

Best protection for fire or smoke.

View More Reviews...
Q: How often do you need to change the batteries?
A: Actual battery service life depends on the particular design of your smoke or carbon monoxide alarm and the environment in which it is installed. All kinds of alarm batteries specified in the user's manual are acceptable replacement batteries. Regardless of the manufacturer's suggested battery life, you MUST replace the batteries immediately once the unit starts "chirping" (the "low battery warning"). It is recommended that you change the batteries in your alarms when you change your clocks for daylight saving time. Also consider replacing your current alarms with 10-Year Life Alarms that never require a costly battery replacement for the ten year life of the alarm. This 10-Year series is available in smoke, carbon monoxide and combination alarms.

Q: What is the proper placement of smoke alarms?
A: It is important that you have the proper placement for your smoke alarms. Install your alarms at least 20 feet from appliances like furnaces and ovens, which produce combustion particles. Alarms should be at least 10 feet from high humidity areas like showers and laundry rooms, and at least 3 feet from heat/AC vents. Be sure to install a smoke alarm in each bedroom, one at the top of each stairwell, and one on every level.

Q: My smoke alarm keeps chirping and beeping. Why does my smoke alarm chirp intermittently?
A: It is likely that the reason your smoke alarm keeps chirping and beeping is that the battery is low. Whenever your smoke alarm keeps chirping, replace the battery immediately.

Other reasons include: It could be a different device or appliance such as a security system, monitor, carbon monoxide alarm, or other device which has a similar low battery or alert signal. Some of the same factors that cause unwanted alarms can cause intermittent alarms: dust and insects in the alarm or power interruptions in hardwired alarms. Improper wiring on AC or AC/DC smoke alarms. AC alarms will chirp every 5 seconds if the interconnect wire is grounded. The orange interconnect wire should NEVER be grounded; it should only be used to interconnect other smoke alarms or compatible devices.

Q: Why doesn't my smoke alarm sound when I push the test button?
A: It is important that you frequently test your smoke alarms. When you are testing your smoke alarm, there are a number of reasons why the alarm might not sound:
  • You may not be holding the test button down long enough. Try holding it down for up to 10 seconds (20 seconds on photoelectric models) .
  • Your battery may not be installed properly or snapped all the way in place. Even if the alarm sounded briefly when the battery touched the terminals, you still need to make sure it is snapped securely in place. If the battery is loose, in cannot power the smoke alarm properly. After installing new batteries, be sure to test your smoke detector.
  • Your AC power may not be on. AC and AC/DC units will have a power indicator light (red or green) that shines continuously when they are receiving electrical power.
  • If you have a 10-Year model, the smoke alarm may not have been properly activated. If the tab broke away before the alarm was activated, you can use a toothpick to move the switch over to test the alarm.

Q: Why does my smoke alarm go off when I install a battery or turn on the AC power?
A: It is normal for smoke alarms to go off and sound briefly (up to 5-10 seconds) when you install a new battery or when they are powered up. If the alarm continues to go off and no smoke is present, the cause may be one of the following:
  • There may be insufficient battery power, try new batteries.
  • Problems with voltage or insufficient electrical power (brown out) may cause a continuous weak sounding alarm. For AC or AC/DC models, temporarily disconnect power at the service panel until the brown out is over. If you do not restore the AC power, your smoke alarms cannot warn you of a fire.
  • Incompatible warning device. If an incompatible alarm or auxiliary device is linked into a series of AC or AC/DC smoke alarms it may cause the system inadvertently go off.

Q: My smoke alarm keeps chirping, even with a new battery. What is causing this?
A: There are a number of possible causes for your smoke alarm to keep chirping even with a new battery.
  • It is possible that your smoke alarm "silence" button was pushed by mistake. The alarm will now "chirp" once a minute for up to 15 minutes before resetting.
  • Are you sure it's the smoke alarm? Funny to ask, but other devices have similar low battery chirps or warning tones.
  • Your "new" batteries may not be fresh. If batteries are stored, especially in cold areas like refrigerators, they lose their charge more quickly. Always check the freshness date on the package when buying new batteries. Keep plenty of replacement batteries on hand so that you are sure to always be protected by your smoke alarms.

Q: I lost my First Alert smoke alarm owner's manual. How can I get a new one?
A: First Alert smoke alarm owner's manuals are available online for download at no cost. Find your alarm in our Smoke Alarms section.

Q: Why does the National Fire Protection Association (NFPA) recommend that home smoke alarms be replaced after 10 years?
A: Smoke alarms have a limited life. Although each smoke alarm and all of its parts have passed many stringent tests and are designed to be as reliable as possible, any of these parts could fail over time. Therefore, you must test the devices weekly. The unit should be replaced immediately if it is not operating properly. The performance of smoke alarms older than 10 years is simply not reliable. To ensure your family's safety, all carbon monoxide and smoke/CO combination alarms need to be replaced every 5-7 years. All smoke alarms need to be replaced every 10 years.

If it's time to replace your alarms, consider the NEW 10-Year Life series and never have to worry about a battery replacement for the life of the alarm.10-Year alarms are available in smoke,carbon monoxide and combination alarms.

Q: I'm ready to change my alarm battery - what replacement batteries can I use?
A: Check your User's Manual or the nameplate on the back of the alarm. Different smoke detectors & CO alarms use different kinds of batteries - 9V, AA, AAA - it all depends on the particular model you have. Use quality batteries like lithium batteries - having plenty of power is worth any extra cost. Never use rechargeable batteries because they may not always provide a consistent charge.

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