NestProtect Smoke + CO Alarm

The Nest Protect Smoke + CO Alarm can send alerts about dangerous levels of carbon monoxide or smoke direct to your smartphone, which is a handy touch if you’re out of the house at the time. This more advanced two-in-one functionality, along with its 10-year lifespan, pushes the price up far above the price of a standard CO alarm. This review is of how well the Nest detects CO, but it's also a smoke alarm and since testing it, the law on smoke alarms has changed in Scotland. This means that as the Nest doesn't come with a heat detection function, it's no longer suitable for homes in Scotland following a 2022 law change. We put the Nest Protect Smoke + CO Alarm through a series of stringent carbon monoxide safety detection tests to find out how well it detects the deadly gas in 2016 and in 2023, we retested it. Read on for the results of our tests.