Nest Thermostat: Models, Compatibility, and Troubleshooting

Google Nest Thermostats

Three current models; the 1st & 2nd gen lost app support in Oct 2025.

Learning Thermostat (4th Gen)

$261.99

Thermostat (2020)

$127.49

Thermostat E

$69.99

Google Nest makes three current thermostats, and the 1st and 2nd generation Learning Thermostats lost app support in October 2025. This hub covers which Nest you own, what it will and won’t control on your system, and every Nest setting and fix on the site.

Which Google Nest thermostat is right for you?

Prices and live availability appear once product data is connected; specs above are per-model capability, not live pricing.

Smart home compatibility

No Nest thermostat speaks HomeKit natively. The Learning Thermostat (4th gen) and the 2020 Thermostat reach the Apple Home app through Matter instead, which covers everyday control but not the full HomeKit automation set. The Thermostat E has neither — if you want Siri or Apple Home, it is not the model to buy.

HVAC system compatibility

Thermostat E limitation: The E supports one stage of heat, one stage of cool, and one additional stage. It cannot manage separate AUX lockout temperatures and is not suitable for multi-stage heat pumps requiring balance-point controls.

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How to identify which Nest you have

If you have an existing Nest and aren’t sure which generation it is:

1. On the thermostat: Press the ring (Learning models) or touch the side strip (2020 model). Go to Settings → Technical Info → Display → Model. Model numbers: G4CVZ = 4th gen Learning; T5001SF = 2020; T4000ES = Thermostat E; T3007ES = 3rd gen.
2. By display shape: The 2020 has a flat rectangular face with a touch strip on the right and no rotating ring. The Learning Thermostat (all generations) has a circular body with a ring you press and rotate.
3. By display finish: The Thermostat E has a frosted white display. All Learning Thermostats have a clear display.

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Symbols and status indicators

The Nest display shows a lot with a small set of icons.

• Nest Thermostat Symbols Meaning Explained: every icon on every Nest model, decoded
• What is Nest Airwave?: the pre-cooling feature that runs the fan to use residual coil coolness
• What is Nest Sunblock?: how Nest detects direct sunlight and compensates
• What is Eco Mode on Nest Thermostat?: eco temperatures when you’re away

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Heat pump settings

Nest handles heat pump systems differently from standard furnaces. The 4th gen Learning Thermostat has the most granular controls available in a consumer thermostat.

• What is Auxiliary and Emergency Heat (EMER) On A Nest Thermostat?: when each mode runs and when to use each
• What is Nest Heat Pump Balance?: the four balance modes (Max Comfort, Balanced, Max Savings, Off) that control AUX staging
• What is O or B Orientation On Nest Heat Pump?: reversing valve configuration; most systems use O, Trane/American Standard use B
• Nest Thermostat Wiring For Heat Pump: full terminal-by-terminal guide

For a head-to-head comparison of Nest’s heat pump controls vs. ecobee’s granular staging settings, see Best Thermostat for a Heat Pump.

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Wiring and setup

• How to Install a Nest Thermostat: complete setup walkthrough, start to finish
• The Nest Thermostat App: what it controls, Eco Temperature and remote sensors, and migrating from the old Nest app
• Can I Use Nest Thermostat Blue Wire as C Wire?: when blue is a spare C wire and when it’s something else
• White-Rodgers Thermostat Wiring to Nest: mapping old WR terminals to the new Nest base
• Carrier Infinity Thermostat Wiring to Nest or Honeywell
• How to Find the Entry Key on Nest Thermostat: the code that links your thermostat to your account
• How to Replace Battery in Nest Thermostat

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Troubleshooting

• Common Problems With Nest Thermostat (With Solutions): the most-asked Nest issues in one place
• Nest Thermostat Low Battery Message/Problem
• Error Code E298 Nest Thermostat (No Power)
• Nest Thermostat Showing Offline in App But Connected to WiFi
• Nest Thermostat Buzzing
• Nest Thermostat No Heat Option
• Nest Thermostat Fan Won’t Turn Off
• Nest Thermostat Blowing Hot Air on Cool: often the O/B orientation setting

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Comparisons and buying guides

• Nest vs ecobee: head-to-head on heat pump controls, multi-room sensing, and smart home integration
• Honeywell vs Nest vs ecobee: three-way comparison for standard systems
• Best Thermostat for a Heat Pump: includes 4th gen balance mode settings

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Should you replace your old Nest?

3rd gen Learning Thermostat (2015): Still receives updates and full app support. The only reasons to upgrade are HomeKit/Matter integration (not available on 3rd gen) or a multi-stage heat pump that needs the 4th gen’s balance point and staging controls.

Thermostat E (2017): Still works and receives updates. The limitation is heat pump support: the E handles one stage only. If you’re on a simple 1-stage gas/electric system and don’t need HomeKit, there’s no urgency.

Signs any Nest is failing:

The 4th gen Learning Thermostat is the current upgrade path for any of the above.

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Frequently asked questions

What does “Aux” mean on a Nest thermostat? AUX means the backup electric resistance strips are running alongside your heat pump. It fires automatically when the heat pump can’t keep up on cold days. If you see “Em” instead, that’s Emergency heat: a manual mode that bypasses the compressor entirely, used when the compressor is broken. Full explanation: What is Auxiliary and Emergency Heat On A Nest Thermostat?

Which Nest model is best for a heat pump? The 4th gen Learning Thermostat. It supports up to 3 heating stages and 2 cooling stages, exposes balance mode controls (Max Comfort, Balanced, Max Savings), and lets installers set the AUX upstage timer and droop threshold. The Thermostat E is not suitable for multi-stage heat pumps (it only supports one heat stage). The 2020 model has basic heat pump support but lacks granular staging controls.

Does Nest work with Apple HomeKit? The 4th gen Learning Thermostat and the Thermostat 2020 both support HomeKit via Matter (requires iOS 16.4+ and a Matter hub like HomePod mini or Apple TV 4K). The Thermostat E and 3rd gen Learning Thermostat do not support Matter and cannot connect to HomeKit.

Does the Nest Thermostat require a C-wire? The 4th gen Learning Thermostat and Thermostat E both use Power Sharing and do not require a C-wire in most homes. The Thermostat 2020 is the exception: it requires a C-wire (or the Nest Power Connector accessory) because its Soli radar sensor draws more power than Power Sharing can supply.

Does Nest require a subscription? No. Core features are free: scheduling, remote control, Home/Away Assist, and energy history. Google discontinued the paid Nest Aware subscription for thermostats. The only paid tier is for Nest cameras and doorbells.

My Nest is showing offline in the app but the display looks fine. What’s wrong? Usually a Wi-Fi channel conflict, router reboot, or network setting change. The thermostat and app lose sync but the thermostat continues controlling temperature locally. See Nest Thermostat Showing Offline in App But Connected to WiFi.

What is the leaf icon on a Nest thermostat? The leaf appears when your setpoint is in the Nest’s energy-efficient range based on your usage history. It’s informational, not an alert. You’re not required to stay in leaf range. Nest Thermostat Symbols Meaning Explained covers all icons including the lesser-known ones.

All Google Nest guides (50)

Every Google Nest guide on the site, A–Z.

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