Note: Before you dive into the specific brand review, we highly recommend you to read our elaborate Thermostat Buying Guide in advance, there are several crucial steps you need to take before you even start to think about the brand.
Nest thermostats are among the hottest controls available, part of the Google empire and compatible with its growing Google Home automation system. The 3rd Generation is the most popular model, though the 2nd Generation is still sold. Nest has also introduced the lower-priced Nest Thermostat E.
How do Nest thermostats compare to one another? Is upgrading from a 2nd Gen thermostat to the 3rd Gen worth it? Those are the issues explored in detail in this Nest thermostat comparison guide. We include Nest thermostat similarities and differences to assist you in deciding the right one for your home.
How Nest 2nd Gen, 3rd Gen and E are the Same
All three are WiFi thermostats with learning technology and compatibility with 95% of 24V HVAC systems (and most systems are 24V). Here are specific ways the Nest 2nd Gen, 3rd Gen and E thermostats are the same.
- Learning: All are programmable but learn too. This means that each time you change a thermostat setting, the data is used in to learn your heating and cooling preferences. When your schedule is regular, the thermostat will automatically adjust heating and cooling settings to fit it.
- WiFi: All allow remote access, monitoring and control using a smart device and an app (iOS and Android). WiFi Wi-Fi – 802.11b/g/n @ 2.4GHz.
- Automation: Work with Alexa and Google Home
- Bluetooth: BLE – Bluetooth Low Energy
- Display: 24-bit color LCD screen. All Nest thermostats feature a rotating adjustment ring and display the current temperature set point and the time, if any, that it will take to reach that temperature. When energy-efficient settings are chosen, the green leaf appears. None of the models have touchscreens.
- C-wire: None of the thermostats require a c-wire, but all might keep temperatures more precise with one. See our Guide to the C-Wire Issue for more details.
- Battery: Built-in, Li-ion rechargeable
- Languages: English, Spanish, French, Italian, Dutch
- Warranty: 1 year
How Nest 2nd Gen, 3rd Gen and E are Different
The table below summarizes the specifications and features of all three models. Below the table is an explanation of differences between Learning Thermostat 2nd Gen and 3rd Gen and between the Learning Thermostats and Nest Thermostat E.
|Nest 2nd Gen||Nest 3rd Gen||Nest E|
|Size||3.27" diameter||3.3" diameter||3.19" diameter|
|1.26" depth||1.21" depth||1.14" depth|
|WiFi||2.4GHz only||2.4GHz + 5GHz||2.4GHz + 5GHz|
|Ambient light||Ambient light|
|Stages||5 total||5 total||3 total|
|Colors||White, Copper, |
3 Differences That Stand Out Between the 2nd Gen and 3rd Gen:
- The display on the Nest Learning Thermostats 3rd Gen is larger display without the entire unit being larger.
- The 3rd Generation Nest has Farsight detection. This means the display will light up as you pass within about 10 feet. The 2nd Generation thermostat lights when you pass within about 3 feet. If you like to view your thermostat from a distance, the Farsight technology will prove useful.
- The 3rd Gen thermostat also supports boiler systems, functionality that’s not possible with the 2nd Gen unit.
Differences Between Nest E and Nest 2nd & 3rd Gen:
Since we’ve covered how 2nd and 3rd Generation models are different, let’s focus on how Nest Thermostat E varies. Essentially, Nest developed Thermostat E to be a low-cost alternative to the Learning Thermostat, a unit that can compete with more affordable smart thermostats like Ecobee and Honeywell Lyric.
Design: The Nest Learning Thermostat has a bold design with strong colors. The Thermostat E’s design is much softer and more subdued. The white frosted display is designed to blend with your décor, not stand out like the 3rd Gen models do.
Compatibility: As noted, all Nest models work with most HVAC systems. This includes gas, electric, forced air, heat pump, radiant, oil, hot water, solar and geothermal. The major difference is their compatibility with staged heating and cooling systems.
–The Learning Thermostats can support 3 stages of heating (wires W1, W2, W3) and 2 stages of cooling (wires Y1, Y2).
–The Nest Thermostat E supports 1 stage of heating (W1), 1 stage of cooling (Y1) and a second stage of either heating (W2) or cooling (Y2).
Additionally, the 2nd Gen and 3rd Gen Learning Thermostats support a system humidifier and dehumidifier while Thermostat E does not. The Nest Compatibility Checker can assist you in determining which models support the HVAC system you have.
Cost: The Nest Learning Thermostat 2nd Generation retails for $249, but since the 3rd Gen introduction, the older model can be bought for closer to $200. There are fewer of them available every day, though, so act fast if you want one. The 3rd Generation unit has a suggested retail price of $249 too, but they’re available from various sellers including Amazon for slightly less. Nest Thermostat E has an MSRP of $169 from Amazon and most other sellers. It can be found for as little as $140, though shipping charges from those retailers might eliminate the cost savings.
There are two final issues to resolve.
3rd Gen vs. Thermostat E
If you don’t yet have a Nest thermostat, the decision for most homeowners is between the Nest Learning Thermostat 3rd Generation and the Thermostat E, since the 2nd Generation thermostat will soon be unavailable except for stray units on eBay or used thermostats.
Nest 3rd Generation or Nest Thermostat E boils down to HVAC stages. If you have more than 3 combined heating and cooling stages, such as a 2-stage furnace and 2-stage air conditioner, you must have the Learning Thermostat, since Thermostat E only supports 3 stages. If you’re unsure what your system’s capabilities are, use the Nest Compatibility Checker. You’ll be asked to remove the cover from your current thermostat to see what wires are being used. That will indicate how many stages it has.
If your HVAC system doesn’t have more than 3 stages, then the issue mostly comes down to cost and appearance. Do you like the looks of the Nest Thermostat E with its subtle white case and frosted display? Then it makes sense to keep the extra $80 in your pocket. When a bright, bold display is important to you because your eyesight isn’t the best or you want the ability to read the thermostat from further away, you’ll be happy with the 3rd Gen Nest Learning Thermostat.
Upgrading from 2nd Generation to 3rd Gen
The new model is brighter and easier to read, and Farsight technology causes it to light when it detects motion from further away. If those are reasons to spend the money on an upgrade, then go for it. Otherwise, wait to see what the 4th Generation Nest Learning Thermostat offers when introduced, likely in the next three years.
Nest Thermostat Wiring
Recently, we just completed an In-depth Thermostat Wiring DIY Guide which covers many wiring situations. Once you select a Nest thermostat and want to wire it by yourself, remember to add this guide to your favorite list. If you come across any questions when wiring your thermostat, feel free to ask a question in the comment sections.
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