Extreme Nest: Taking your smart thermostat to the next level with zones and sensors

The Nest system is remarkably powerful and flexible for smart home heating and cooling. David Gewirtz shows how he's using multiple Nests to manage zoned HVAC and adding sensors and even control temperature on a room-by-room basis.
Written by David Gewirtz, Senior Contributing Editor

Video: Extreme Nest: Take Nest to the next level with zones and sensors

One of the challenges of buying a fixer-upper is doing the actual fixing up. The house we just bought -- located in a small historic Oregon town -- needs a lot of work. The biggest project was heating and air conditioning. In this article, I'll tell you about that project, and how I'm taking Nest thermostats to the next level by using them to control zones and even individual rooms.

The house we bought is interesting. We work from home, so we don't only need living space, we need space to do our jobs. That's not as easy to find as you might think, especially in our price range. We found a really cool house that meets our needs, but also needs a lot of work.

The house started as a smaller building when it was first built. That portion is built over a crawl space with ducts for heating. A previous owner walled in the chimney and decided to put the furnace into a closet, blocking it off with a privacy divider from the rest of the hall. It was pretty sad.

Read also: 10 ways Alexa can help you get work done - TechRepublic

There are two other areas of the building, a living area built right on top of a concrete slab, and a garage, also built on top of a slab. Based on discussions with a neighbor who knew the previous owners, the living area on the concrete slab may have once been a garage itself. We're not sure when the current garage got built, but there it is.

In any case, the entire second half of the house came with no heating or AC. No ductwork. The previous residents had scattered a bunch of space heaters throughout the house, and that's how they kept warm in the winter. They didn't have any solution for keeping cool in the 90-degree summers.

That wouldn't work for me. I start to get cranky whenever the temperature breaks 70 (Fahrenheit). There's a single upstairs loft room, which will become my office, and that room is hot-hot-hot without air conditioning.

Over the past five weeks or so, we removed the old furnace, and put in a new three-zone HVAC system that is serving the whole house, including areas that have never seen ducting. As you'll see in the accompanying video, the HVAC professionals we worked with did some seriously creative ductwork to make it happen.

Each zone is controlled by a Nest E thermostat. Although there's a lot of magic involved in hooking up the zoned AC system, which we left to a licensed pro, the thermostats themselves are identical to what I installed last year in our temporary rental house.

As it turns out, there's a lot of depth in the design and engineering of the Nest, far more than I was aware of when I installed the single zone thermostat in the house I've been renting for the past year.

The Nest app controls each of the zones. In fact, because I'm still living in the temporary rental house, my Nest app has four zones listed, three for the new house, and the original zone in the rental house.

While the zone control is helpful, it doesn't handle one serious problem: That upstairs office loft. Fortunately, Nest has an answer. But, first, let's explore the problem.

The Nest takes its temperature reading where it's mounted on the wall. In the case of the zone with my office (which also has my bedroom), the Nest thermostat is mounted on a wall in a hall. If I set my desired temperature to 70 degrees, the Nest will make sure that spot in the hall stays at 70 degrees.

Read also: Google brings Nest into the game as its AI battles Alexa - CNET

That's fine, but during the day, it's my office I want to be at 70. At night, I'd prefer my bedroom be 70 (or cooler). If you rely simply on the wall thermostat, you have to do what we've done for decades: Dial down the temperature and hope the rooms at the edge will get cool enough (or warm enough, for winter months).

But Nest has introduced little mini puck sensors. These things are $39 each (although I bought a set of three for $99). For some reason, they're not sold by Amazon, so you'll have to go to Google to order them.

You connect the sensor (I show you how in the accompanying video) to your Nest app and assign it to a given thermostat. From that point on, you can choose which sensor's reading will control the temperature in a given zone.

You can also program this in, which is ideal for me. I put one sensor in my upstairs office (which is usually about 15 degrees warmer than downstairs). I put another in our bedroom. During the day, the sensor in the office controls the temperature, and we cool the zone until my office is 70 degrees.

At night, the sensor in the bedroom controls the temperature, and we cool the zone until our bedroom is 70 degrees (which means the office will likely be substantially warmer).

By using the sensors, combined with zoned thermostats, we have an unprecedented level of control over our comfort throughout the house -- which will be nice if we ever finish renovations and actually get to move in.

Also, I'd like to send a shout-out to the folks at Synology. Although I like the Google Wi-Fi mesh network, its reach depends on having Wi-Fi pucks scattered throughout the house. With contractors constantly marching through the house and moving things around, the potential of them unplugging or moving the pucks is huge.

To reach all parts of the house to talk to the thermostats, I needed a router with enough punch to make it through a wide range of building materials that make up our new house, which is why I reached out to Synology.

I also wanted to put in a couple of cameras that I could access remotely. After driving the 45 minutes down to the new house at the crack of dawn a few times, only to be stood up by contractors, I wanted to be able to see if they'd arrived before I made the trip to the house. I paired Synology's DS916+ with Surveillance Station and a couple of cheap Wi-Fi cameras, and I was able to save myself a couple of unnecessary round trips.

Read also: Using the Nest E with Alexa: A cool tool for staying warm

I haven't subjected the RT2600ac router to exhaustive testing, but it's been strong enough to reach every corner of the house. Big thanks to Synology for sending it to me. I'll have more coverage of both the Surveillance Station software and the router as this project progresses.

Back to the Nest: I haven't yet spent time living in the new house, so I can't really tell you from experience how the multiple zones and sensors work on a day-to-day basis. But I've been sufficiently happy with how Nest works with Alexa in the rental house that I made it a criteria that our HVAC system had to support Nest. The multiple zones combined with sensors, so far, seem to be meeting our needs.

What's cool is that I can tell the temperature of each zone and sensor remotely. So even though I'm writing this from our rental house, which is 45 minutes away by car, I can check my Nest app and confirm the temperature in each zone. It's the middle of the day, and right now, even though it's 93 degrees outside, my office is a cool 70 degrees. For the contractors who are working so very hard, it's nice to know for sure that we have the air conditioning working so well.

Have you used Nest in a complex application? Let me know in the comments below.

You can follow my day-to-day project updates on social media. Be sure to follow me on Twitter at @DavidGewirtz, on Facebook at Facebook.com/DavidGewirtz, on Instagram at Instagram.com/DavidGewirtz, and on YouTube at YouTube.com/DavidGewirtzTV.

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