Our Emerson Sensi WiFi thermostat rating:
(4.5/5)

Emerson Sensi at a Glance

The Emerson Sensi is our go-to smart thermostat recommendation for installations without a C-wire, shoppers on a budget, and anyone in need of a “simple” smart thermostat that still does virtually everything you might want it to.

Our hands-on experience with the Sensi was simple and straightforward: a family member had a winter cabin they wanted to monitor and adjust the temperature of remotely, the Sensi made it possible. That was back in 2016, and the Sensi’s been a “fire and forget” solution for that home.

It just works

Here’s our Sensi, installed in 2016:

The on-unit controls are fairly limited. You can raise/lower the temp, turn the fan on/off (if there is one), and tweak the schedule, but for nearly all of these things it’s easier to do them through the app or through a linked assistant. We link our thermostats to the Google Home app and control them there, but we found the Sensi app intuitive and easy to use.

Sensi HVAC Compatibility

No C-wire is required if your system is:

• Conventional heating and cooling, such as a gas furnace, air conditioner, electric furnace, or boiler

You will need a C-wire if your system is:

• Heat-only gas furnace, electric furnace, or boiler
• Cooling-only (just an air conditioner)
• Heat pump

Sensi’s own website offers a handy compatibility checking tool.

Like most (if not all) smart thermostats, the Sensi is not compatible with line voltage and proprietary systems, gravity furnaces, in-floor, or millivolt wall systems.

Sensi Favorite Features

There’s a lot to love about the Sensi, but here’s some of our favorite features. For a longer list of features, check out Sensi’s own website.

Different schedules for different days. Generally, we like being able to set different schedules for each day of the week, since our work from home days and children’s schedules vary.

Early start feature starts heating or cooling “ahead of time” so the house is at the desired temp by the time you want it to be that temp.

Price point. For the way we use a thermostat, the hardware mounted to the wall doesn’t matter that much. We do all of our control through the app or the Google Home app. For that reason, we liked saving $100 (or more) versus buying a pricier smart thermostat. With flagship thermostats like the Nest and Ecobee, a lot of what you’re buying is the fancy touch screen, and in our case we didn’t mind not paying for a touch screen we didn’t need.

Sensi Drawbacks

You can’t schedule the fan independently. Say you want the fan to come on when you go to bed and stay on until you get up – Sensi didn’t make this available in the app. At least, they didn’t at the time of this writing (2021). It’s always possible they’ll add it.

It’s not a stylish thermostat. That’s fine with us, but don’t buy this for your spouse who asked for a Nest for Christmas. It’s got a plasticky feel to it and the buttons have that 1990s feel to them. That said, you may not want a futuristic-looking thermostat on your wall. (This one really comes down to personal taste.)

Swing range too tight for some users. Swing range preferences vary by user – some people want the house held at 72 degrees no matter what, even if it means the heating comes on/off more frequently. Some people don’t care if the house drops to 69 before the heat kicks back on and they don’t want the heating coming on/off so often. This is purely a personal preference thing, but the important thing to know here is that the Sensi lets you adjust what they call the “cycle rate”.

Not a panacea for all systems lacking a C-wire. As much as we wish a WiFi thermostat could run entirely on two AA batteries, the Sensi cannot. No WiFi thermostat can. If you have no C-wire, the Sensi will only work for you if you have both heating and cooling. If you only have heating or cooling, you will need to run a C-wire or consider something like the Venstar Add-a-Wire.

No “local” (intranet) control. This isn’t unique to the Sensi, but if you were hoping for a smart thermostat you could use without going through someone’s cloud server, the Sensi isn’t it. (At the time of this writing, all of the major smart thermostats are like this.)

Great app, easy to use

Scheduling, overrides, and settings are right there on the smartphone app, which is nice looking and easy to figure out. The app is available for iOS (reviews and screenshots) and Android (reviews and screenshots). The worst complaint about the app seems to be the occasional inability to connect.

Installation and setup

You’ll need to make an account with Sensi (through the app) when you set up your new Sensi thermostat and register your device. Be sure to write down the access code found on the back of your Sensi before you mount it to the wall, because you’ll need it during setup (if you forget, though, no big deal – it’s also included on a sheet of paper in the box).

On my first setup attempt I accidentally neglected to finish registering the Sensi thermostat – and that prevented it from fully integrating itself with my app. So that’s my one bit of advice for setup: be sure to complete the registration step, or else you’ll be wondering why your thermostat doesn’t show in the app.

Once you’ve got the setup complete, your Sensi app will change to reflect the current mode and temperature.

(I’ve edited the name and location out of these screenshots because this is one of my own, not manufacturer’s screenshots.) 

The upper right corner of the app’s default screen shows today’s high and low temperature, as well as current temperature and location.

From here, you can set up schedules and adjust the current target temperature via the “hotdog” (or “hamburger”) menu in the upper left corner. A tray pops out to show schedule options, settings, account info, access to help, and more.

Overall, we found the app straightforward to navigate and use.

In the box

• Sensi Wi-Fi thermostat
• Thermostat base
• Quick start guide
• Mounting screws
• Wire labels
• Security code card for hooking up with the web portal and app
• 2 AA batteries

The bottom line

The Sensi is a great thermostat well worth it’s low price tag.

We love the low cost, ease of installation, and the way you don’t really sacrifice anything by going with this “budget” model. For us, it just worked – and that’s all we wanted. We installed ours in 2017 and five years later in 2021 it’s still going strong.

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