Buyer's Guides Holiday Guide

Best WiFi-enabled Smart Thermostats of 2018 – Holiday Buyers Guide

We are back with a brand new edition of our annual buyer’s guide! Whether you’re giving (or hoping to get), this quick guide will help you figure out which WiFi thermostat is right for you.

What’s new this year

This year was light on new models, but a number of updates and new accessories hit the market:

  • Nest rolled out a temperature sensor accessory for their flagship thermostat, the Nest Learning Thermostat, and Nest Thermostat E!
  • Ecobee expanded their product line with the Switch+, an Alexa-enabled light switch
  • Virtually everyone’s got Alexa and Google Home integration now!
  • Sensi owners will soon get emailed monthly usage reports

How do I tell if a smart thermostat is compatible with my home?

Nearly all of the popular smart thermostats on the market today (Nest, Ecobee, Sensi, etc.) are meant for use with a 24-volt HVAC system (often called forced air or central heat/air conditioning). If you don’t know what you have, check out our guide to identifying your HVAC system type here.

If you have a line-voltage heater, such as electric baseboard heating or a thermostat that controls an electric heater in every room of your home, look at the bottom of this article for our recommendations.

About us: Thanks for joining us! We’ve been installing, reviewing, and generally obsessing over smart thermostats since 2014. We are a team of technology nerds who install and test the thermostats we review in our own homes to bring you hands-on expertise and opinions. This guide is current as of November 2018 and is intended for North American shoppers (sorry, UK – you guys have totally different stuff). 

Overall best smart thermostat for 2018: ecobee4 Smart Thermostat

Read our hands-on review: ecobee4 with Alexa built-in

No surprises here, the ecobee4 is what we’ve been recommending all year, for several years running. The HVAC contractors we’ve talked to agree: the ecobee is the most reliable, most compatible smart thermostat on the market today.

Why is still our favorite?

  • Superior compatibility and reliability, thanks to the included Power Extender Kit that acts as a “motherboard” and ensures the thermostat unit has enough power to run
  • Easy to schedule with an intuitive app design that lets you copy/paste schedules and quickly override existing schedules as needed
  • Best usage reports that show how long your system ran and when
  • Built-in Alexa makes it easy to control the temperature even if your hands and phone are busy
  • Included room temperature sensor lets you monitor the room (or rooms) that matter most
  • Add additional room sensors to see exactly which parts of your home are getting the heat (or cooling) they need.

Besides reliability, the Ecobee is basically the full-featured smart thermostat of our dreams. It’s easy to install, easy to use, and easy to basically forget about once you’re up and running (which is how a thermostat should be). The app is great, but if for whatever reason you find yourself standing at the thermostat itself, the high-res touch screen feels almost exactly like a phone and is a joy to use. We think the room sensor accessories are great, too – using one in our home helped us understand just how much colder the baby’s room is compared to the rest of the house. We’re set up with Alexa, too, so the on-board Alexa was a nice treat, but if you’re not into Alexa disabling it is a perfectly fine choice (and it won’t glow red or nag you about it being turned off, either).


Both! The ecobee4 is the smart thermostat to give (and get!) this winter. It’s a sexy flagship model that’s sure to wow anyone you give it to, and it’s the most likely to be compatible with the recipient’s existing 24v HVAC system wiring.

See the ecobee4 on

Best “old school” smart thermostat: Emerson Sensi (works without a C-wire in many systems)

Read our hands-on review: Emerson Sensi

Years ago, thermostats needed hardly more power than a wristwatch and could run for years on a couple AA batteries. The advent of WiFi connectivity in thermostats, however, necessitated the use of the C-wire to supply continuous power. (Read more about the C-wire here)

This Sensi model gets a lot of love from us not just because of its overall simplicity and affordable price, but because it doesn’t require a C-wire. This sets it apart from nearly all the other smart thermostats on the market right now, except for the ecobee4 (which comes with a kit you can attach to your furnace to make up for a missing C-wire).

Searches related to the lack of a c-wire drive a lot of this website’s traffic, and we’ve heard from a large number of people over the years who just want something simple that’ll work with the wiring they already have.

For those people, we recommend the Sensi for that reason as well as the following:

  • Easy to install and compatible with a wide variety of systems
  • Easy to schedule with an intuitive app design that lets you copy/paste schedules and quickly override existing schedules as needed
  • High customer satisfactionJD Power’s highest ranked in 2016
  • Large display and buttons are easy to read and press
  • Monthly emailed usage reports give basic insight into your HVAC system’s usage

Sure, it doesn’t have a touch screen, but once you’ve got it set up you’ll probably only adjust it through the app anyway. Our own Sensi has been quietly humming along in a winter cabin for two years now. The WiFi isn’t great out there (it’s mooched off a neighbor, in fact) but the Sensi has remained responsive and reliable.


Get. Since it’s not nearly as sexy as the full-color, touch-screen offerings on the market right now, we think it’s better to gift this one to yourself unless you know your recipient’s home lacks a C-wire and they cannot upgrade their wiring.

PS: Sensi recently came out with a touch screen version, but this model requires a C-wire. Here is our review of the touch screen version of the Sensi.

See the Emerson Sensi on

Most “hands-off” smart thermostat: Nest Learning Thermostat or Nest Thermostat E

Read our hands-on reviews: Nest Learning Thermostat (3rd gen.) and Nest Thermostat E

Nest now offers two smart thermostats: the one on the left is the flagship model with the most complete support for HVAC system accessories. This model offers seven different color ring options. The one on the right is a more budget-priced model, with slightly more limited HVAC accessory support. It only comes in white with a unique “frosted” screen look. Both have the same “brains” and offer the same learning algorithm that tries to take the guesswork and effort out of setting up an energy-saving schedule.

The Nest sells itself on its effortlessness: after a brief setup, you’re done and Nest takes it from there, figuring out when you’re home and when you’re out and what temperatures you prefer. It will try to nudge you towards energy-saving settings, but that doesn’t mean you have to accept a too-cold or too-warm home. You can tell it you’d rather it be 72 instead of 70 and it will remember that preference.

In theory, the “learning” feature should take a lot of the work out of programming the thermostat. In reality, though, Nest’s learning leaves a lot to be desired. Many Nest owners end up manually setting up schedules and skipping the automatic “learning” stuff. Whatever you tell it in the first week or so is what it runs with until you override or reset it, and it’s pretty bad at figuring out a schedule that isn’t a super standard Monday-to-Friday 9-5 schedule. The ideal Nest user is probably a single person (or couple) who work a typical “day job” outside the home. If you work shifts or part time or have multiple people in your home for whom those things are true, Nest’s “learning” is going to feel pretty dumb. Our take: just schedule it yourself. It’s easy to do via the app and much easier than playing a guessing game.

But there’s more reasons to consider the Nest rather “hands-off” compared to the competition. If you have a collection of Nest products in your home, they can all work together – no need to manage each one individually in its own app. The Farsight feature (3rd gen. Nest) responds to your presence as you walk by (and displays either the time or the temperature – pick one). The interface is easy to navigate, both on the Nest itself and in the app. Once we set up a schedule, we thought the Nest could be described as “set it and forget it”.

New in 2018: the Nest now supports up to six room temperature sensors. Unlike the ecobee room sensors, these sensors do not detect motion or occupancy. However, they are still useful for using some other room’s temperature reading in determining when to kick on the heat or run the air conditioning. Read our review of the Nest temperature sensors here.

Some things we love about the Nest: 

  • Integrated with all the Nest home automation products, so you can manage everything from one app
  • Shiny and sleek design is sure to turn heads and make your home feel futuristic
  • High customer satisfaction, topping J.D. Power’s smart thermostat customer satisfaction list two years in a row
  • Easy to schedule through the polished app (since the “learning” stuff is probably going to let you down anyway)
  • Control via Alexa or Google Home unit elsewhere in your home
  • Recent usage statistics in the app 
  • Add up to 6 additional room sensors to see exactly which parts of your home are getting the heat (or cooling) they need.

Why we don’t recommend the Nest for homes without a C-wire: Nest’s compatibility checker tells a lot of people that their 4-wire (no C-wire) setup is sufficient for a Nest. However, we have heard many complaints about the Nest eventually turning up dead in these systems. The 4-wire setup might be good enough for a little while, but the Nest will slowly lose power and eventually stop making heat calls to the furnace. It’s anyone’s guess whether this will happen to you, but this is why we suggest the Ecobee or the Sensi for homes without a C-wire. (Read more about the risks of installing a Nest without a c-wire here.)


Both! But we think it’s best to gift the flagship model, since it’s more likely to be compatible with the recipient’s system and it’s the model everyone who wants a Nest tends to want. For extra brownie points and wow factor, grab a room sensor (sold separately) to pair with your gift.

Alas, we can’t help you with picking a color ring that your recipient is guaranteed to love. Our favorite ring colors are the white and the polished steel. The mirror black is a fingerprint magnet and brass and copper might be difficult to match with the recipient’s decor (they also have kind of an old-fashioned look that we think is at odds with the bright, boldly colored screen.) So, that’s our recommendation: get a white, silver, or steel ring if you’re buying for someone else and don’t know their preference.

See the Nest Learning Thermostat on

A few more suggestions

Best thermostats for data nerds

By default, thermostats from Ecobee, Nest, and Sensi generate monthly usage reports that get emailed to you after the month is over. (Sensi reports are new as of November 2018)

They’re somewhat useful – the data they provide is summarized and doesn’t tell you much (no year-over-year comparisons, and they don’t try to turn your usage into dollars saved). Still, these are the only two manufacturers making any effort at usage reports, and what they do generate might be enough to make some users happy. In general, though, and we say this as huge data nerds – the reports are a disappointment no matter who they’re coming from.

Fortunately, some third party projects are now aiming to fill that need.

For Ecobee users our favorite dashboard is beestat. The application links up with your Ecobee data (as saved on the Ecobee website) and displays a dashboard of recent usage statistics for your HVAC system. This web-based application is only for Ecobee thermostats right now, but a Nest version is in the works. Using beestat requires no special knowledge.

For Nest users, lets you download all of your usage data and parse it however you please. Obviously, you need to be technically inclined to actually analyze it, but if you’re shopping for someone who likes to tinker around with Excel or coding projects, they might enjoy the opportunity to parse their own data. (Or just wait for beestat to expand to Nest.)

RelatedOur guide to third party apps for analyzing Ecobee and Nest data here.

Best smart thermostat for someone who doesn’t have a C-wire in their 24v HVAC system

Go with an ecobee model. Ecobee thermostats are the most reliable over the long haul, in our experience, because every ecobee ships with its own motherboard (the PEK) to make up for a missing 5th wire. Other choices either require a C-wire or charge themselves by “pulsing” your HVAC sytem, which is not always reliable in every system over the years.

Best smart thermostat for someone without a 24v HVAC system

Sorry, there still isn’t much to pick from for homes with heaters in every room, millivolt heaters, baseboard heating, etc. We own a property with a mini split system and we eagerly await the day we can recommend a smart thermostat for such a system. If you have electric baseboard heaters, check out the Mysa. (We have not used Mysa ourselves but it looks well-reviewed.)

And that’s it for 2018!

We hope you found this guide useful! We’ve been trying and reviewing thermostats for five years now, so if you still aren’t sure what to buy, ask us for recommendations in the comments!

From all of us: we hope you have a wonderful and warm holiday season!

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