Nest Protect Smoke and Carbon Monoxide Alarm

Last updated: October 7, 2020

The Nest Protect Smoke and Carbon Monoxide Alarm is a unique type of carbon monoxide detector, also providing smoke detection. This is a smart alarm, which means it hooks up to your home's Wi-Fi and lets you monitor your CO levels using an app. If you do have an evacuation, the Nest detector will light a path to help you get out even if it's late at night.

We looked at the top Carbon Monoxide Detectors and dug through the reviews from some of the most popular review sites. Through this analysis, we've determined the best Carbon Monoxide Detector you should buy.

Product Details

Key Takeaway: This combo carbon monoxide detector and smoke detector hooks up to your home's Wi-Fi and can be monitored from an app.

In our analysis of 47 expert reviews, the Nest Protect Smoke & Carbon Monoxide Alarm placed 2nd when we looked at the top 9 products in the category. For the full ranking, see below.

From The Manufacturer

It’s time to expect more from your smoke alarm. Nest Protect has been redesigned from the inside out. It has a Split-Spectrum Sensor, tests itself automatically and lasts up to a decade. It’s also the first home alarm you can hush from your phone without any extra hardware required. And it tells you what’s wrong and can even alert your phone. Nest products are made to work together. And they can even work with lights, locks and other products in your home. The Nest Protect can alert the Nest Thermostat when it detects carbon monoxide and the Thermostat can turn off the furnace to try and reduce the leak while you get to safety. Nest is focused on making simple, human, delightful things. That’s how we’re creating the thoughtful home: A home that takes care of the people inside it and the world around it.

Expert Reviews

What reviewers liked

The Nest Protect uses a split-spectrum sensor that Nest says is good at detecting both slow-smouldering fires as well as fast-burning ones.
Combination smoke alarm/CO detector
With automated rules that can safely light a path out of your home and a choice of battery-powered or wired models available, the Nest Protect is a smart smoke alarm.
It uses both photoelectric and ionization sensors to detect both smoldering and full-on burning fires
Nest’s uses what they call a Split-Spectrum Sensor, which, while photoelectric, promises to detect fast-burning fires more quickly, more in line with the performance of ionization sensors.
The app notifies you whenever the battery is low and self-checks the alarm regularly to ensure it’s still working properly.
- Tuck
When an alarm is tripped, Nest Protect gets to work alerting you not just via its alarm, but also via a color-coded LED on the top of the device (yellow for low levels of smoke or CO, red for a “get-out-now” level of danger).
The Protect has built-in sensors to detect electrochemical CO, heat, humidity, occupancy and ambient light, as well as a microphone.
Uses a speaker and calm voice to tell you whether smoke or carbon monoxide was detected, the room it’s in, and its level of danger

What reviewers didn't like

At $100, the Nest Protect is one of the most expensive, but also one of the most comprehensive, of the smart smoke detectors we've tested
CO readings not given in PPM
There’s no getting away from the fact that it’s expensive, however.
I have to admit, I’m a little wary of entrusting something as important as a smoke alarm to a smart device.
These alarms are expensive compared with a standard smoke and CO alarm.
At over $100, this carbon monoxide detector isn’t cheap, but for those who want the security of monitoring their CO levels anywhere with their smartphone, the price may be worth it.
- Tuck
Nest Protect isn’t cheap, but even at $119 it’s not the most expensive smart smoke detector on the market.
Nagating the Nest app is pretty straightforward, but it has some quirks. From the main screen you can initiate a safety check whenever you like to ensure that the alarms are working and, supposedly, review your history. But, although I've tested the Protect over several days, no history has ever populated in the app
Reported complications in troubleshooting problems, including Wi-Fi disconnection and locating certain types of routers
View our Carbon Monoxide Detector buying guide for in-depth advice and recommendations.

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