As its name suggests, the temperature sensor works in conjunction with the Nest Thermostat (and the Nest Thermostat E) to let you control the temperature in individual rooms. If you set one in the bedroom, for example, you can then configure the Nest app to esnure that room is colder or warmer than the rest of the house. The price for a single unit is $39, or $99 for a pack of three. You can preorder it starting today, and it'll begin shipping next month.

As part of the announcement, Nest recently walked me through some of its connected-home product family's new features. We saw much of it already at last year's Nest event, but it was good to see how all of it comes together. Of course, you can buy these products individually and they'll work fine by themselves, but the beauty of the Nest ecosystem is when it all works together.

In our demo, Nest showed me a series of hypothetical home scenarios where its connected home system would come in handy. For example, if someone is at the door, the Nest Hello video doorbell would immediately recognize that there's someone there. If you're a Nest Aware subscriber, you'd not only get a notification on your phone that there's a person at the door, but the facial recognition feature would kick in too. Basically, once the same person comes to your door enough times, you can train Nest's Familiar Face Alerts to identify him or her, perhaps as your mother or your neighbor John. I tried an early version of this feature with the Nest Cam IQ Indoor, but it wasn't very good back then. Hopefully, the newer version will fare better.

If you happen to have a Google Assistant-enabled device in your home -- say a Google Home Mini or maybe the new Nest Cam IQ Indoor -- those will give you Nest Hello notifications too. They'll either say "Someone's at the door" or, if you have a Nest Aware subscription, the name of that person as well (eg. "John's at the door").

From there, you can check out who your guest is by looking at the Nest app. The interesting thing about the Hello's camera its vertical 4:3 ratio, so that you can see the person from head to toe. In my demo, I was pretty impressed by how sharp the HD quality was, and I liked that you could pan the camera left and right to see what else was around. I should note here that the Hello needs to be hardwired to your house's electrical system, while the Ring smart doorbell just needs a rechargeable battery. This could be good or bad depending on how you see it -- hardwired means it'll never run out of power, but it also means the Hello is a lot harder to install.

A Nest spokesperson told me that the Hello also has a "quiet time" mode that is basically a Do Not Disturb function for your doorbell, which is good for when, say, the baby is taking a nap. You'll still get push notifications on your phone, but that's it.

And if you want to let John in and you have the Nest x Yale Lock installed, you can just unlock the door right in the app. And hey, if your house has the Nest Secure security system installed, unlocking the Yale Lock will automatically disarm the alarm as well.

Speaking of Nest Secure, Nest's director of product marketing, Maxime Veron, said Nest added a few new features to the home security system since last year's launch. For one thing, Nest Secure now has an "instant alarm." Before, Nest Secure would give you a 30-second delay when turning it on, to allow you enough time to leave the house without setting off the alarm. But, based on customer feedback, now you can just instantly turn it on, which offers more peace of mind, especially when arming your house before going to bed.

Next, is the ability to arm your Nest Secure just by using Google Assistant. So, you can say "OK Google, set Nest Secure to away," and that would then automatically turn Nest Secure on, giving you 30 seconds to leave the house before the alarm is set. And, yes, if you have the Nest x Yale Lock, you can have that automatically lock the house a few seconds after that as well. In the demo, this happened a lot longer than I would like -- around a minute or so -- but according to Veron, that can timing can be adjusted. Oh, and if you have a Nest Cam, you can have that automatically turn on when you leave the house as well.

I should mention here that Nest told me that you can use Google Assistant only to arm Nest Secure, and not to disarm it. Which is good, because you don't want any ol' stranger to break into the house just by giving a voice command.

Also, it's worth pointing out how different the Nest Cam IQ Indoor is with the new Google Assistant integration, which we didn't have a chance to test out before. In my demo, this new feature almost turns it into a pseudo Google Home device -- it can answer basic Google queries like "What's the weather?" and "How tall is the Eiffel Tower?" The only thing it can't do that a Google Home can, is continuous audio playback, like playing music or podcasts. But if you don't care about that, then getting a Nest Cam IQ Indoor is like getting a webcam and a Google Home in one device, which is pretty neat.

Going back to new Nest Secure features, you can now set the hub to chime whenever certain doors open, sort of like when you enter a store and a bell rings. To go along with this, Nest also added a "Quiet Open" option, where you can press a button that'll disarm the door for just the one time -- if it's early in the morning, for example -- and then it'll go right back on after you leave.

"We started on this mission six years ago, with the thermostat," said Veron. "But now we have 12 products in the catalog and have sold over 11 million products. [We believe] Nest is synonymous with the smart home."

That said, Nest is still something of a latecomer to the industry; it's not the first to come up with a wireless security system, and the Nest Hello is obviously a response to the popular Ring smart doorbell. And now that Amazon has purchased Ring and has its own Cloud Cam security camera as well, it's clear that Nest will have a lot of competition going forward.

It also bears mentioning that Nest products tend to be on the expensive side. While the Hello will retail for $229, you can get the Ring for around $134 on Amazon. Amazon's Cloud Cam is also only $120, while the regular Nest Cam Indoor is $200 (The IQ version is about $100 more). You have to pay at least $5 a month to get any kind of video archiving with Nest Aware (if you don't pay anything, all you get are still snapshots for the past three hours), while Amazon's Cloud Cam video archives are free for the past 24 hours.

Still, Nest is betting hard on its connected home dream. That could certainly be why Google recently decided to merge its hardware teams, which would bring a heavy dose of Google-powered AI to the Nest party. And with Google-imbued smart displays from the likes of Lenovo and LG coming up, it's easy to see how Nest products would incorporate all of that and more.

Veron himself gave a hint that this is still early days in the Nest and Google marriage. "You'll see a lot more Nest and Google integrations in the year ahead," he teased. With rivals nipping at its heels and Amazon seemingly cutting off Nest products from its website, it'll likely need as much support as it can get.