Best answer: Yes. Up to 10 Nest Protects can be used with the same Nest account, in one or multiple locations.
Amazon: Nest Protect ($119)
Multiple Nest Protects are supported
You probably have more than one smoke alarm in your home right now, and that's because multiple units are needed according to national and local law. The National Fire Protection Association (NFPA) regulations for residential dwellings — single family homes that don't house a business or provide care services — say you'll need an alarm in multiple areas, including all sleeping areas, every level that's separated by a door, new homes built since 2007, and for certain-sized dwellings, one every 500 square feet of floor space.
Luckily, your Nest account allows up to 10 Nest Protects enabled at once and these can all be in the same location or spread across several different locations (we recommend the latter).
And you're going to want to get that full protection. Nest Protects are both smoke and carbon monoxide detectors, so you'll be covered. However, it goes beyond just a typical smoke detector. Nest Protects are smart, so they can not only regulate themselves but have multiple settings, including a Home/Away Assist feature that uses sensors to detect whether you're home or not. It can also contact up to 20 people via smartphone if one of them goes off.
Best of all, because they're smart, they won't deafen you while going off. That's literally music to our ears.
If you're replacing or adding smoke detectors, the Nest Protect is your best buy.
A smoke detector needs to warn you when appropriate, and not give false alarms. The Nest Protect excels at both and also provides excellent carbon monoxide detection. Because they're from Nest, they are easily integrated into any home automation plan and work with Amazon Alexa and Google Assistant.