Who can appear for the NEST exam

Nest Protect: the noble smoke detector from Google in the test

Stephan Wiesend

The Protect smoke alarm from Google subsidiary Nest is not cheap, but it offers interesting special functions.

EnlargeThe Nest Protect has also been available in Germany for some time.

As soon as you unpack it, you notice that the Nest Protect should meet high standards. The high-quality packaging is reminiscent of Apple products, the relatively large smoke detector is packed in an additional transparent cover. At 119 euros per device, it is not exactly cheap, as you can get conventional fire detectors for ten each. Compared to the Techem smoke alarms, which have been spoiling the author's rented apartment since last year, the device already has the better design. It is relatively large for a smoke detector, but thanks to the good product design, it shouldn't be a problem. At Amazon, a device costs 119 euros, the 3-pack a little cheaper 329 euros.

EnlargeSix lithium batteries ensure a long runtime.

Installation and administration

The configuration is similar to that of our two earlier Nest test devices (Nest Cam Outdoor and Nest Cam Indoor). Incidentally, there is no on or off button: To start up, you pull on a small blue strip of paper. This closes the contacts of the batteries and the device starts. A female voice then guides you through the commissioning of the device, for example a short signal test.

With a size of 13.5 x 13.9 x 3.9 cm (W / H / D), the Nest Protect is comparatively large and weighs 381 grams and is also significantly heavier than conventional smoke alarms. When installing on the ceiling, the installer should therefore have some manual experience.

Configuration is child's play, however: You install the Nest app on your iPhone and scan the QR code on the back of the Nest Protect. Now you can give the device the WiFi password and manage the device completely via the iPhone app. In contrast to the Nest Cam, the management options are of course limited. You can start a system test and assign a room such as “study” to the device. If desired, WLAN, alarm, voice output, battery and sensors can be tested. A green signal light shows that everything is OK.

If you mount the device on the ceiling, six high-quality lithium batteries ensure a long operating time. You should be informed about dying batteries six months in advance, according to the manufacturer, the device tests itself 400 times a day. What you should also know: The devices only log into the WLAN network once a day in order to save energy. They then appear as offline in the app.

Alarm function

In the event of an alarm, Nest Protect offers more than a conventional DIY smoke detector: A small loudspeaker is integrated that not only emits signal tones, but also speaks German-language warning messages with additional information. The female voice not only guides you through the configuration, but also provides information such as: “Warning! Smoke alarm in the study! ”Unusual: Nest Protect differentiates between warning message and alarm: If there is little smoke or carbon monoxide, for example because of a burnt meal, there is a warning and a yellow warning signal. There is only a real alarm and a red warning light when there is a high amount of smoke.

At the same time, the messages also appear in the app. Good: If the smoke disappears again quickly, you will also be informed about it. You can also mute the alarm not only by pressing a button but also by smartphone - for example when you are not in the apartment and a neighbor informs you about the alarm. With the first generation of Protect devices, this was only possible by pressing the control button on the device. In addition to smoke, the Protect can detect carbon monoxide (CO) and also reports this via voice output, which makes the device interesting for users of a gas stove or stove, for example. The sensor should work for ten years.

EnlargeYou are also informed about problems via the app.

If desired, the device can detect movements and switch on its signal light. The Protect can thus serve as a kind of night light that switches itself on and off automatically. According to user reports, however, this function should reduce battery life.


To test the device, Nest provided us with a spray from "No Climb Products" that can be used to simulate smoke. In our test, both the alarm function and the Nest app worked without any problems. Overall, the device made a good impression on us, we only see some room for improvement in terms of size. Since we can only check the performance of smoke alarms and carbon monoxide sensors with our test equipment to a limited extent, we refrain from giving a final score.

Nest Protect

Price: Euro 119
Advantages: Easy installation, CO sensor
Disadvantages: Relatively large, the night light function reduces the battery life
Manufacturer: Nest

Other devices from Nest:

To test the Nest Cam Indoor

To test the Nest Cam Outdoor