Face-Off: Ecobee4 Smart Thermostat vs. Nest Learning Thermostat
Only two smart thermostats use remote sensors to make the whole house comfortable. Which one is right for you?
Nearly all thermostats operate solely based on the temperature reading of the room they're in. That can make other rooms of your house controlled by the same thermostat uncomfortable if, say, the thermostat is on a wall that gets a lot of sun.
Only two thermostat makers, Ecobee and Nest, have a solution: wireless remote temperature sensors. You place them in hot or cold rooms and they factor those temperature readings into the thermostat's programming to make those areas more comfortable.
Each brand's top-of-the-line models, the Ecobee4 and Nest Learning Thermostat, work with these remote sensors. Despite that similarity, and the fact that both models perform well in our lab tests, the two thermostats are far from identical.
How We Test Smart Thermostats
At CR, we’ve tested hundreds of thermostats over the years. Once upon a time they weren’t very accurate, but today’s models are able to keep rooms close to the set temperature. So instead of testing for temperature accuracy, our labs focus on usability. That includes testing ease of manual operation (with the same standards we use for nonconnected programmable thermostats) and three criteria specific to smart thermostats: smart-home features, automation of heating and cooling, and wireless setup.
Our evaluation of smart-home features examines such elements as alerts, app control, and geofencing (which tells the thermostat when you’re coming and going). These individual features factor into a thermostat’s Smart IQ score, which allows you to see just how “smart” one thermostat is compared with another.
For automation, we check to see whether smart thermostats learn your habits and routines to adjust temperatures for you. And we test wireless setup, which includes connecting the thermostats to WiFi and setting up the corresponding smartphone apps. We also set up voice control with Amazon Alexa, Google Assistant, and Apple Siri if integrations with these digital assistants are available.
Findings from all these tests are folded into a model’s Overall Score, a straightforward, at-a-glance view of our comprehensive test results.
The CR Face-Off: Ecobee vs. Nest
Both the Ecobee4 and Nest Learning Thermostat let you make temperature changes and program heating/cooling schedules from a smartphone app as well as on the thermostat itself. You can also control both thermostats with your voice via digital assistants found on smartphones and smart speakers. The Ecobee offers Amazon Alexa built-in (it's like having a small smart speaker right on your wall) and works with Apple Siri, Google Assistant, and Microsoft Cortana. The Nest works with all of these except Apple Siri.
When you move past these various control methods, the differences become more apparent.
The Ecobee4 lets you create vacation schedules to save energy when you’re away for multiple days. But the Nest can learn your temperature preferences and comings and goings to automate temperature changes; no scheduling or programming required.
The Nest also offers geofencing, the ability to automatically change the temperature when you leave and return home based on your smartphone's location, for multiple users in the same home. The Ecobee offers geofencing but only for Android and Apple HomeKit users. If you simply use an iPhone by itself (HomeKit requires an additional Apple device be left in the house), you’re out of luck.
The Ecobee comes with one remote temperature sensor in the box, while the Nest’s remote temperature sensor is a $40 accessory (additional Ecobee sensors come in $80 two-packs).
Ecobee’s remote sensors also detect occupancy, which allows the thermostat to prioritize that temperature reading (or take an average of multiple sensor readings) to sufficiently heat or cool occupied rooms.
Nest's remote sensors don't detect occupancy, nor can their temperature readings be averaged with the Nest thermostat's own readings to try to balance heating/cooling. Instead, the Nest thermostat can switch between using either the remote sensor or the thermostat's temperature sensor for heating/cooling, all based on a schedule you create. For example, you could have the thermostat switch to using your bedroom sensor at night when you're sleeping, then go back to the thermostat's built-in sensor during the day.
Whether you need these sensors, though, depends on whether your thermostat has trouble heating/cooling some of the rooms in your house. For example, if you have one room that’s always hotter or colder than the rest, one sensor will suffice. But if you have multiple problem spots, you’ll need multiple sensors—and the cost can quickly add up in either case. (The Ecobee4 supports up to 32 remote sensors, and the Nest thermostat supports up to six sensors.)
When it comes to performance in our lab tests, the Nest Learning Thermostat beats the Ecobee4 in two crucial ones: Smart IQ and automation. The Nest receives strong scores for these tests due to its ability to make temperature changes for you by learning your behavior and because of its wider array of smart features.
"We reward automation in our testing because it is a fundamental premise behind smart devices and removes the need for consumers to fuss about their appliances," says Anzalone. "But if you're the sort of person who prefers to make temperature changes yourself, automation may not be as important to you."
In our manual operation test, the Ecobee comes out ahead of the Nest, earning a stronger score due to its more intuitive controls and its touch-screen interface, which mirrors the app interface, making it easier to switch between the thermostat and your phone. Both the Ecobee and Nest receive the same middling score in our WiFi setup test.
The thermostat wiring for your HVAC system can vary significantly and use anywhere from two to five wires. Most smart thermostats require one of those wires to be a common wire, or C-wire, which provides a constant flow of power to the device. (You can learn more about C-wires in our thermostat buying guide.) The name of this wire is a bit ironic, though: C-wires aren’t all that common, especially on older HVAC systems.
Neither thermostat requires a C-wire, but there are some caveats. If you have a two-wire system, only the Nest will work. If you have more than two wires but no C-wire, the Ecobee is a better choice because it comes with a special power extender kit that essentially turns one of the wires into a C-wire for your thermostat. And while the Nest doesn’t technically require a C-wire, some HVAC professionals caution against its workaround (it charges its built-in battery by running your HVAC fan), saying it can damage your system.
If you have a C-wire, either model should work just fine.
Keep in mind that you will need to hire an electrician if you're not comfortable with electrical wiring. If you are, you can find basic instructions in our guide to installing a smart thermostat.
At the end of the day, the best smart thermostat we’ve tested is the Nest Learning Thermostat. It offers important smart features, such as geofencing, and true automation of your heating and cooling.
But if you prefer more strict temperature schedules—perhaps because your family's got a locked-in routine—with some added smart features such as voice control, the Ecobee4 might be a better choice for you.
The other major factor? Your home’s HVAC system and that (often missing) C-wire. The Ecobee offers an easy and compelling way to get around the missing wire. Or you can purchase a $28 add-a-wire adapter if you’re set on installing the Nest.
For other smart thermostat options, check out our smart thermostat ratings.