Buyer's Guides

Best smart thermostats of 2018 – summer shopping guide

Summer’s here! Can your thermostat keep up?

If you’re still turning your AC on and off with a dial or a few buttons on a thermostat you never programmed, then you’ll love the simple, hands-off automation of a smart thermostat. If you have a 24-volt HVAC system (often called forced air or central heat/air conditioning), there’s a smart thermostat out there for you. But which one should you pick? Check out our guide to the best smart thermostats of summer 2018!

About us: We’ve been installing, reviewing, and generally obsessing over smart thermostats since 2014. Thanks for joining us! This guide was written for North American readers and is current as of July 2018. We hope you find it helpful!

Good news, Amazon Echo fans. All of the thermostats featured in this article support Alexa.

The best smart thermostat for most homes: ecobee4

Ecobee stuffed Alexa into a thermostat and it’s fantastic.

ecobee4 quick look

Pros Cons
  • Room temp/motion sensor included
  • Power Extender Kit for systems without a C-wire
  • Lovely touch screen
  • Great app
  • Alexa built into the hardware
  • Also works with Google Assistant and other home automation systems
  • Strong support from Amazon
  • HomeIQ reports aren’t even close to real-time: it takes a full month to get your first one
  • Have a lot of Nest products in your home? The ecobee won’t work with them the way the Nest thermostat does.
  • Ecobee has been slow to roll updates out to older models

The ecobee is the one to beat this year. Everything you need to get started is in the package: the ecobee4 unit, a room sensor, a Power Extender Kit to help with wiring, and Alexa built right into the hardware. While all of the thermostats in this round up “work with Alexa” via an Echo somewhere else in your house, the ecobee4 is the only one with Alexa built right in. It’s (almost) like having an Echo Dot inside your thermostat.

See our detailed hands-on review of the ecobee4 here.

We recommend the ecobee4 “for most homes” because ecobee includes a Power Extender Kit with every thermostat shipped. If you don’t have a C-wire, then the kit should be able to help by allowing one of the wires you do have to effectively “act” as two wires, where the PEK interprets the signal and determines if the thermostat needs power or just wants the fan to run.

The included Power Extender Kit goes inside your furnace and acts as an additional bit of brainpower to make one wire act like two and compensate for a missing C-wire. It “re-purposes” a wire without actually re-purposing it, effectively giving you a C-wire where you didn’t have one before.

The little white plastic doodad is a wireless temperature and motion sensor that you place somewhere else in your home, away from the main thermostat unit. This is awesome for homes where the thermostat is in a less-than-ideal location (such as right in front of a sunny window, or in the darkest corner of your hallway). You can build more sophisticated schedules that take into account just the sensor’s temperature reading, or just the sensor’s reading at particular times of the day. Basically, the sensor lets you say “I only care about this room, so run the air conditioning (or heat) until this particular room is comfortable”. (You can add additional room sensors, too.)

Put the ecobee’s sensor in another room and read that room’s temperature instead.

Nest added a similar external temperature sensor last month to its product line, but all theirs does is sense temperature – the ecobee’s sensors also sense motion, which can be used to direct the main unit’s heating and cooling efforts to the rooms people are actually in.

The ecobee4’s touch screen is beautiful and easy to use, even for those of us with large, not-so-pointy fingers, but you won’t spend much time standing at the thermostat adjusting it, anyway, because the app is excellent. Set up your schedules and then forget about it – we found we stopped messing with it within a couple days, and only use the app to override the default programming when needed.

The ecobee4 has Alexa built in and works with any additional Alexa devices you might have, Samsung’s SmartThings, IFTTT, Apple HomeKit (so you can control it through Siri and your Apple Watch), and Google Assistant (Google Home and Google Home Mini). Also, disabling the integrated Alexa can now be done without making a red “error” light glow on the top of the unit, thanks to a November 2017 firmware update.

The data geek in your family will be pleased by ecobee’s HomeIQ reports, which are detailed and offer some built-in data analysis, and tinkerers might be tempted to play with ecobee’s open API (ecobee Chrome extension, anyone?). The HomeIQ reports are slow to generate, though, so don’t expect up-to-the-minute usage data (alas).

The bottom line: the ecobee4 is the smart thermostat to get this summer

See the ecobee4 on

The “hands off” smart thermostat for people in the Nest ecosystem: the Nest Learning Thermostat

Nest thermostats quick look

Pros Cons
  • Part of a fantastic suite of home automation equipment, including cameras, smoke detectors, a security system, and more
  • The “learning” algorithm aims to create a hands-off, energy-saving schedule for you
  • You can purchase a room temperature sensor separately
  • Long lifetime of support expected now that Nest is back in the Google fold
  • Needs a C-wire
  • Schedule-learning can be finicky and less helpful for families with variable schedules

Nest makes a large family of products these days, from smart cameras to smoke detectors to home security systems. These are high quality products and if you’re interested in jumping into the Nest ecosystem, we won’t deter you. The Nest Learning Thermostat and the Nest Thermostat E (see the differences here) are both excellent choices, but we recommend them more to people who want to fill their home with a variety of Nest products. We think ecobee is stronger overall thanks to its motion-detecting room sensors, touch screen design, and better scheduling options.

The biggest drawback with the Nest is the need for a C-wire, but you can overcome that problem with a Venstar Add-a-Wire or by running new wire altogether (learn more about what to do if you’re missing a C-wire here).

Nest got even better this year with the addition of its very own room temperature sensor accessory. Sold separately, the small wireless sensor lets your Nest thermostat pick up a temperature reading from somewhere else in the house and act accordingly. This is perfect for homes where the thermostat is located somewhere particularly warm or cool, and it’s just plain useful for getting better control over the rooms you care about most in your home.

Both the Nest Learning Thermostat (the flagship model) and the Nest Thermostat E (the “budget” model) feature the same “learning” algorithm that made Nest famous in the first place. This is perfect for people who want to “set it and forget it”, but the caveat is that it doesn’t deal as well with variable schedules. Nest also has a rather firm idea of when people want to schedule things, giving pre-defined windows such as 7am-11am, 11am-2pm, 2pm-7pm, and

Are you someone who wants to “set it and forget it”? (Or are you shopping for someone like that?)

The Nest Learning Thermostat and the Nest Thermostat E are perfect for buyers hoping to see a reduction in their monthly energy usage. The Nest’s award-winning design is all about nudging you towards energy-efficient settings with its on-screen “Leaf” icon that rewards you for choosing an energy-efficient temperature and monthly reports show you how well you did compared to others in your zip code.

Of course, you can always tweak the schedule it came up with or override its defaults.

Both thermostats have the same “brains”, so pick whichever one works with your system (if you have a lot of accessories or a humidifier, you’ll need to get the full-featured Nest.)

All smart thermostats are great for saving energy, but we think Nest has the edge thanks to its monthly energy reports.

Then you want the Nest Learning Thermostat. The Nest sells itself on its effortlessness: once it’s powered on, you’re done – Nest’s smart “learning” algorithms will take it from there. It looks at the current weather, whether you’re home or away, and works out your schedule on its own. The schedule it creates optimizes for savings and comfort by not heating an empty house or not turning on the AC until you’re on your way home.

If you’re one of those people who leaves your thermostat set to 70 degrees day in, day out, you’re going to love what the Nest can do for you (and your wallet).

See the Nest Learning Thermostat on

Also: Check out the Nest Thermostat E. The Nest Thermostat E doesn’t support some combinations of accessories and it doesn’t support humidifiers (if you already use a separate humidifier control panel and thermostat, then you can just replace your thermostat with the Nest Thermostat E and keep the separate humidifier control).

Best budget smart thermostats under $100: Emerson Sensi and Honeywell RTH6590WF

This Emerson Sensi is a WiFi-enabled, Alexa-enabled thermostat with a design reminiscent of programmable thermostats. The Sensi is still one of our top picks, budget category or not, and for good reason: it’s capable, pleasing to look at and touch, and it works without a C-wire. We set one up in a family member’s vacation cabin last winter and we have been pleased with its reliability. We hear a lot of “I just want a basic thermostat but with an app” – if this is you, then the Sensi is the way to go.

Read our full Emerson Sensi review

It lacks a touch screen but who cares? Once you have a WiFi-enabled thermostat you never need to stand in front of it again.

Emerson Sensi quick look

Pros Cons
  • Works without a C-wire
  • It’s like a programmable thermostat with WiFi capabilities
  • App design is pleasant, with large numbers and buttons
  • Easy to use
  • Great price
  • The unit itself feels a bit lightweight, but you won’t interact with it much anyway

See the Emerson Sensi on

Another popular choice in the “under $100” bracket is the Honeywell RTH6580WF. Honeywell is a trusted name in thermostats and the RTH6580WF is built on decades of thermostat-building experience. It’s got an old-school look but WiFi and “smart home” capabilities (including support for Alexa, SmartThings, Wink, and more). The only drawback: it requires a C-wire, so make sure you have a C-wire before choosing this thermostat.

A popular choice for vacation homes, this Honeywell adds WiFi features to a classic design.

See the Honeywell RTH6580WF on

These “budget” models win points with us for their simplicity and affordability. They both come with smartly designed apps that will meet your needs, and the price is especially helpful for anyone needing to purchase multiples.

Best-selling smart thermostat (according to our data): Emerson Sensi and ecobee4

We looked at which thermostats readers of this site are most likely to buy (and least likely to return) and found that the two most popular choice is the Emerson Sensi (followed very closely by the Ecobee4). Neither thermostat requires a C-wire, which we think might be a big part of why they are so popular. Running additional wires can be a hassle depending on your home’s layout, and many homeowners are looking to keep installation simple. The Sensi is undoubtedly popular thanks to its affordable price, robust feature set, and easy-to-use interface. (And if you’re bummed about the lack of a touch screen – check it Sensi’s new model, the Emerson Sensi Touch Wi-Fi Thermostat with Touchscreen.)

No c-wire required and a simple design: we love the Sensi, and it looks like everyone else does, too!

See the Emerson Sensi on

And that’s it for summer 2018!

We hope you have a wonderful – and cool – summer!

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.