The Best Basic Smoke Alarm

We spoke to a number of people in the fire-safety industry:

We had multiple conversations with the team at UL, the organization responsible for smoke alarm safety standards, testing and research. This included Dwayne Sloan, technical director of Built Environment at UL Solutions; Diane Haithcock, standards program for UL Standards & Engagement; and Steve Kerber, vice president and executive director of UL Research Institute’s Fire Safety Research Institute. We also spoke with John Drengenberg, then consumer safety director.

We also spoke with:

• Joseph Keenan, then assistant fire marshal of the Burlington Fire Department in Burlington, Vermont
• Judy Comoletti, then division manager for public education at the National Fire Protection Association (NFPA)
• Timothy Sendelbach, then editor-in-chief of Firehouse Magazine, with 30 years of experience in fire and safety services
• Tom Kiurski, training coordinator and director of fire safety education for Livonia, Michigan, as well as a columnist with FireRescue1; Kiurski has more than 35 years of experience in the fire services

In addition, we spent hours reading hundreds of pages of smoke-alarm studies, such as the NFPA’s extensive “Smoke Alarms in US Home Fires” report, the National Center for Healthy Housing’s “Evaluation of the ‘10-Year’ Smoke Alarm Project” report, and Vision 20/20’s “The Smoke Alarm Problem” report, among many others. Note that the National Center for Healthy Housing is partially funded by The Home Depot Foundation.

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Working smoke alarms are essential in any home, but you should treat them as just one piece of a comprehensive fire-safety plan. Your plan should include other safety items such as fire extinguishers and escape ladders, but most importantly, you should base your plan on an awareness of what to do in case of a fire. Firehouse Magazine’s Timothy Sendelbach told us, “The best advice I can offer is to practice fire drills, using the test button on the alarm, to familiarize family members with the sound and recommended actions to be taken upon activation.” For more information, we recommend the NFPA’s page on how to make a home fire escape plan.

It’s important to understand your state and local smoke alarm regulations before making a purchase. We found that many regulations are at odds with one another—and with our recommendations. No company sells a one-size-fits-all smoke alarm capable of satisfying the requirements of every state.

For example, our top pick, the First Alert SM500V, uses two AA batteries, but many states now require models with 10-year sealed batteries. We have a recommendation to meet that requirement, as well.

First Alert’s site has a nice interactive map that can help you understand your state’s requirements. We also recommend contacting your local fire department for more information specific to your area.

A smoke alarm must conform to the latest UL standards. We can’t stress this enough. Compliance with the latest UL standards means you’re getting a smoke alarm that contains the latest smoke detecting technology and a device that has been verified by a third-party laboratory (typically either UL or Intertek).

UL certification has always been a requirement of ours, but it has only become more essential with the most recent revisions to UL smoke alarm standards. These latest standards are targeted at eliminating the two most common issues with smoke alarms: the need for a greater sensitivity to burning polyurethane foam and reduction of cooking nuisance alarms.

Over the past four decades, homes, and how they are furnished, have changed dramatically. Where people once used natural textiles and wood furniture, they now have synthetic fabrics and furniture made of composite materials. Changes like these, in addition to an increase in open floor plans, have resulted in homes that burn faster than ever before. According to UL’s Steve Kerber, “Forty years ago, people had 17 minutes to escape their homes in the event of a fire.” Now, he told us in an interview, that’s down to “the three minute time frame.”

To show this difference, UL conducted a study comparing how natural and synthetic materials burn. Two living rooms were created and furnished with similar items, but one used synthetic furnishings and the other used natural furnishings. The rooms contained a couch, end tables, lamps, and other common items. A fire was lit in the same place on each couch; after four and a half minutes, the fire in the room with natural furnishings was still contained to a corner of the couch, while the room with synthetic furnishings was completely engulfed in flames. We recommend watching the video.

But, alongside this increased sensitivity to burning polyurethane foam, a smoke alarm now must be able to identify cooking smoke and not sound off in order to reduce nuisance alarms. Research, like this study done on rural Alaskan homes, has shown that these unwanted alarms cause people to disable their smoke alarms, leaving them with no early warning fire system at all.

So the goal of the latest revisions to the UL standards is to have an alarm “intelligent enough to be able to tell the difference between a cooking nuisance alarm and an actual fire that can cause harm,” said Kerber.

In order to gain certification, an alarm must pass a performance test with burgers being broiled a certain distance away. The National Institute of Standards and Technology (NIST), a part of the US Department of Commerce that deals with product standards, ran an extensive study comparing new smoke alarms with legacy alarms and found little difference in the number of nuisance alarms between the two. But that’s not to say the standard is insignificant. It’s the opposite, actually. As the study from NIST notes, the new standard, “does provide a performance baseline to ensure newer alarms that need to meet the more stringent flaming and smoldering fire tests are not overly sensitive to nuisance sources.” So while there may be little difference in performance between old and new alarms with regard to cooking alarms, no ground is lost as the devices become more and more sensitive to burning polyurethane foam.

In addition to these standards creating smoke alarms more attuned to our modern day homes, they also make purchasing a smoke alarm much easier because they’ve essentially eliminated the distinction between photoelectric alarms and ionization alarms, which were the two styles of alarm available in the past. Each of those technologies has its positives and negatives, and the recommendation was to have both styles in your home. It could be difficult to understand the difference, and it resulted in a redundancy of alarms in the home. Now, as long as you’re buying a model that is manufactured to the most recent standards, you have what you need.

Interconnected alarms: One way to increase the fire protection of your home is to get interconnected smoke alarms so that when one goes off, they all do. Keenan, of the Burlington Fire Department, referred to this connectedness as “the biggest feature which makes a smoke alarm effective.” The main advantage is that such an arrangement allows for “early notification of all residents within the dwelling, no matter where the problem originates.”

Many states require interconnected, hardwired smoke alarms with a battery backup in all new construction. Retrofitting this kind of wiring into a house is expensive, so some new battery-powered smoke alarms use a localized wireless technology to link units. Overall, our research convinced us that recommending interconnected models should be a main focus of this guide.

Affordable and accessible models: We wanted to find alarms that are relatively easy to set up and for which the cost is as little of an obstacle as possible. So we looked primarily at basic or “dumb” models that run on AA batteries. (We have more to say on batteries in the Maintenance section.) Smart smoke alarms usually cost more than twice the price of our pick (and that cost compounds when you need to purchase multiple units). When it comes to actual smoke- and fire-detection abilities, the difference between the best smart alarms and the best dumb alarms is not significant enough to be a dealbreaking factor. The major difference is that smart models allow you to monitor your home’s smoke alarms remotely via an app. Beyond that capability, smart smoke alarms offer additional features and smart-home integration. To learn more, see our separate guide to the best smart smoke alarm.

Some other basic alarms have a number of features that we didn’t prioritize, such as lights or specific alert noises. Those are nice, but as training coordinator and fire safety educator Tom Kiurski told us, “The options are what drive up the price.” He added that “having plenty of working smoke alarms is most important.”

Top pick

The best basic smoke alarm

First Alert SM500V Interconnected Battery-Operated Smoke Alarm with Voice Alerts

These alarms are built to the most recent standards and can interconnect so that they all sound at once. They also tell you which room the fire is in.

Buy from Amazon

May be out of stock

$71 from Walmart

(pack of two)

May be out of stock

$55 from Lowe's

For your primary line of defense, we recommend the First Alert SM500V Interconnected Battery-Operated Smoke Alarm with Voice Alerts. This alarm is built to the most current UL standards, meaning it’s designed to give fast notification of burning polyurethane foam. If you get two or more units, they link together through a wireless signal so that they all sound at once. In addition, each is assigned a location so that when one alarm goes off, all of the units indicate which room the fire is in. The alarm is a voice alarm, which research indicates is more effective in waking small children than a high-pitched tone. The First Alert SM500V is the only alarm we found that combines the voice alarm, the location feature, and the wireless connection all in one unit—at a price that’s merely on the high side of average for the category.

The wireless connection is the most important feature for early detection of a fire. Upon installation, the SM500V alarms connect to one another with just a couple of button pushes on your part. As for the range of the wireless connection, the instruction manual for the SM500V says that each one is typically 100 feet, although “some features of a home, such as the number of levels, number/size of rooms, furniture and types of building materials used may reduce the range of the Alarms.” The company gives examples such as “suspended ceilings, ductwork, large metallic appliances (refrigerators) and metal studs.”

The SM500V units use what is called a mesh network, which means the signal is not linear from one unit to the next. The benefit of this technology, according to First Alert, is that “the mesh network of alarms re-routes and resends the signal via the other alarms, providing a greater chance all alarms will receive the signal.” It’s important to note that these alarms are connected only to one another and have nothing to do with a phone app or a household Wi-Fi connection. You can expand the network to a maximum of 12 alarms. Also, the alarms link “through the software using 65,000 security code combinations,” according to First Alert, minimizing the chance of interference from a duplicate code in a nearby home.

This alarm tells you where the fire is. During initial setup, you assign each alarm a room location. When the alarms go off, they all announce the source alarm’s location. As training coordinator and fire safety educator Tom Kiurski told us, “Vocal smoke alarms are recommended if you have children between 4 and 12 years of age, because studies show they respond better to a familiar voice, as opposed to something that can fall under ‘white noise.’”¹

It’s easy to set up. Getting the SM500V’s up on your walls and ceiling is a predictable process, in the sense that it involves light screwdriving and some alarm sounds blaring in your face. To attach the mounting plate to the wall, you may need to drill and drive a few new drywall screws, but no heavy-duty mounting hardware or stud finding is necessary for this task. In a nice touch, the units come with AA batteries included. And although assigning the units to certain rooms and pairing them together was loud and a little confusing, we followed the included instructions, and everything worked correctly the first time. Finally, a reader asked us if you have to go around to each paired alarm to manually turn each one off during an alarm or test. The answer is no—conveniently, when you deactivate one, they all go silent.

You should have more than one. We recommend using these First Alert alarms as your principal line of defense, with one on each floor and one in each bedroom, adding more units to account for the size of your house. We also believe it’s important to have a carbon monoxide detector as well as an ionization alarm on each floor for added protection against the hazards they’re suited for, and we have suggestions on those below.

Flaws but not dealbreakers

The main downside of the SM500V is that it isn’t particularly attractive. It looks like, well, a smoke alarm. First Alert has other models with a thinner look (such as the SM210V), but to get the wireless connectivity and the voice and location alerts in a single unit, your only option is the model we’re recommending. The good news is that once smoke alarms are installed, everyone stops noticing them.

Best for...

Best for equivalent protection, plus a CO alarm

First Alert SMCO500V Interconnected Battery-Operated Combination Smoke & Carbon Monoxide Alarm with Voice Alerts

Like our top pick but with a carbon monoxide alarm, this interconnected model can also detect elevated CO levels from faulty fuel-burning appliances.

Buy from Amazon

May be out of stock

Carbon monoxide is a deadly, odorless, colorless gas that can spread through a home as the result of a malfunctioning or improperly installed chimney or combustion appliance such as a gas stove, a gas boiler, a water heater, a propane range, or a wood stove, according to the Environmental Protection Agency and other sources. If you don’t already have CO alarms, we strongly recommend including a few First Alert SMCO500V Interconnected Battery-Operated Combination Smoke & Carbon Monoxide Alarm with Voice Alerts units in your interconnected system.

This model offers the same features as our top pick (wireless interconnectivity, voice alarm, and location alerts) and adds a carbon monoxide sensor.

Best for...

Best for locations with a 10-year battery requirement

First Alert SM210 10-Year Sealed Battery Smoke Alarm with Slim Profile Design

The SM210 can’t interconnect like our picks, but it does have a 10-year sealed battery, which some states and municipalities require.

$33 from Amazon

$34 from Walmart

Many states (such as California) and municipalities (such as Phoenix) require smoke alarms with 10-year batteries. For these areas, we recommend the First Alert SM210 10-Year Sealed Battery Smoke Alarm with Slim Profile Design, which, as its name indicates, has a fully sealed 10-year lithium-ion battery. The alarm has a low profile from the wall of about an inch, and looks a lot more streamlined than our top pick (though it doesn’t have the voice alert or wireless connectivity). It typically costs around $25, making it a relatively inexpensive option. First Alert sells a similar model with a pathway light that turns on when the alarm activates.

One purported benefit of the sealed battery is that it offers a higher degree of tamper resistance because it is not removable. But keep in mind that when you take the alarm unit off the wall, it deactivates.

Even though this alarm is sold with a 10-year battery, it still requires testing on a regular basis. A study prepared for the Centers for Disease Control and Prevention did a long-term follow-up on alarms and found that 14% of those using lithium-ion batteries had dead batteries before the full 10 years were up.

The NFPA’s recommendation for smoke alarm placement is that you have one in each bedroom, one outside of each sleeping area, and one on each floor. So for a typical two-story home, that’s one in the basement (preferably near the stairs to the first floor), one on the first floor, and one in the second-floor hallway, with an additional unit in each bedroom. You should not place one in a garage (due to car exhaust) or in areas that have temperatures lower than 40 degrees Fahrenheit or higher than 100 degrees Fahrenheit.

As for the specifics of a smoke alarm’s location within a room, there are actually quite a few areas to avoid. First Alert’s FAQ states, “Install smoke 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.”

It’s important to check your smoke alarms on a regular basis. Kiurski recommends doing so monthly and says to “change the battery as suggested by the manufacturer.” According to the NFPA, “Manufacturers’ instructions are specific to the batteries (brand and model) that must be used. The smoke alarm may not work properly if a different kind of battery is used.” And don’t use rechargeable batteries, according to the manual for the First Alert SM500V.

First Alert says batteries should be replaced once every six months. Most alarms start to chirp when the batteries are low. Make sure not to treat such sounds as nuisance alarms—don’t ignore them.

The alarms we recommend all sound at 85 decibels, which should be loud enough for most people, but if you have hearing loss or are just a heavy sleeper, there are other options to consider. Items like the Lifetone HL Bedside Fire Alarm and Clock and the SafeAwake Smoke Alarm with Bed Shaker pick up the alarm sound from a standard smoke alarm and flash lights, emit a loud low-frequency alert, and vibrate a pillow shaker.

With placement on the shelves of Home Depot, Kidde is the most prominent competitor to First Alert. Their most up to date line of smoke alarms is called Detect and they have models with features similar to the recommended First Alerts. The downside is that Kidde's overall track record is, in a word, disturbing. In 2021, the company recalled 226,000 smoke and combination smoke/CO alarms. In 2018, they recalled more than 450,000 dual-sensor smoke alarms. In 2016, another recall involved 3.6 million smoke/CO alarms. In 2014, another 1.2 million smoke and smoke/CO alarms were recalled. In addition, since 2005, Kidde has enacted four separate fire extinguisher recalls of 470,000 units (2005), 167,000 units (2009), 4.6 million units (2015), and 37.8 million units (2017). In early 2021, a federal judge ordered Kidde to pay a $12 million civil penalty “in connection with allegations that the company failed to timely inform the Consumer Product Safety Commission about problems with fire extinguishers manufactured by the company.” For these reasons, we can’t in good conscience recommend any Kidde products to our readers.

Although First Alert is not immune to recalls (it recalled nearly 150,000 smoke alarms and combination smoke/CO alarms in 2006 and roughly 600,000 fire extinguishers in 2000), none of them are recent or on the scale of what Kidde has had to do.

Universal Security Instruments has a line of smoke alarms that have been designed and tested to the latest standards. They look to be nice items, all with sealed 10-year batteries, but they don’t offer the wireless interconnectedness or the voice alarms of our top pick.

X-Sense smoke alarms are small and look a little nicer than most. Some of its products are similar to our picks, most notably the X-Sense XS01 Wireless Interconnected Smoke Alarm (available in a three- or six-pack). Unfortunately, it doesn’t have a third-party certification, so it’s impossible to tell how they stack up against the competition or if they are in compliance with the latest UL standards, which were designed to eliminate nuisance alarms.

This article was edited by Harry Sawyers.