Adding Wi-Fi doesn’t always turn out to be as smart as it sounds. A smart smoke detector turns out to be dumber than I thought, even with Wi-Fi added.

Smart smoke detectors will let you know if a fire breaks out when you aren’t home, but other than that they don’t offer any extra benefits over a “dumb” model. And these devices introduce a problem: Most smart smoke detectors exclude one of two sensors to alert you about a fire. Every smart model I tested had only a photoelectric sensor, which picks up smoldering fires, while ionization sensors that pick up fast-burning fires were left behind. Ionization sensors are more likely to have nuisance alarms go off (while you’re cooking, for example), but it’s still a sensor you should have somewhere in your home, especially since modern building materials have shortened your window of time to escape a home fire.

It’s not to say smart smoke detectors are useless, since what matters most is having a working smoke detector at all. A photoelectric-only smoke detector is still a good smoke detector and will pick up smoldering electrical fires in your walls and similar-style smoke. Still, you’ll want to make sure there is an ionization sensor or two in your home, more so than needing a Wi-Fi model added. There are dual-sensor smoke detectors you can get too, but no smart models just yet with both sensors. Here’s everything you need to know if you’re considering getting a smart smoke detector for your home.

Does a Smoke Alarm Need to Be Smart?

You already know what a smoke alarm is: a device that sits on the ceiling (or sometimes high up on a wall) to alert you if it senses smoke in a home or building. Most buildings, whether residential or commercial, come equipped with modern smoke alarms to match current codes. In recent years, it’s been another device to go “smart,” or at least become Wi-Fi compatible. It’s not smart the way a smart thermostat would be, since you can’t meaningfully exert control over it over Wi-Fi. You’ll simply get alerts on your smartphone of choice when smoke is detected, so you’ll know if a fire happens while you aren’t home, in addition to the blaring of the regular alarm.

Is it necessary? No, but it’s a nice-to-have feature to get alerted, no matter where you are, if smoke is detected. But it’s not required to make these devices function, and it won’t help you with the speed at which fires are moving through newer homes.

“While newer smart features like Wi-Fi alerts and app connectivity can be convenient, they’re not essential for safety,” says Steve Clemente, president and COO at Mister Sparky, an electrical services company. “A well-placed, properly powered detector will do far more to protect your home than extra features like air quality monitoring. One exception worth considering is a combo smoke and carbon monoxide detector, which adds an extra layer of protection.”

How Do Smoke Alarms Work?

Smoke alarms have built-in sensors to sniff out smoke in your home. There are two primary sensors included: photoelectric and ionization. “Photoelectric models are better at sensing slow, smoldering fires—like upholstery or wiring—while ionization models respond faster to quick, flaming fires,” says Clemente.

He says neither is universally better, and rather the two styles are complementary. The National Fire Protection Association recommends having both types of smoke alarm sensors in your home, or a smoke alarm that has both sensors built into it (these are usually called dual-sensor smoke alarms). The NFPA doesn’t have any specific codes about which type of sensor you need to put in your home, but a spokesperson did recommend putting photoelectric smoke alarms near kitchens and bathrooms, since they’re less likely to be set off by daily use in these rooms (things like steam and cooking smoke are more likely to set off an ionization alarm).

However, all the smart models I tested included only photoelectric sensors. As I continued researching, most smart smoke alarms seem to only include photoelectric sensors, leaving out ionization altogether. It’s likely because of the sensitivity of ionization alarms. That’s a problem for me after talking to Nicole Sanders, public education lead for UL Research Institutes’ Fire Safety Research Institute, who warned me that new data shows you might only have three minutes to escape a house fire.