Smart Thermostats
Best Energy Saving Thermostat (2026): 5 Picks Compared
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For the best energy saving thermostat, the Google Nest leads with ENERGY STAR certification, app control and operation without a C-wire. The ecobee runner-up adds a room sensor, air quality monitor and 3-year warranty, while the Sensi adds geofencing with a 3-year warranty.
Starting out? See the main guide: Best Smart Thermostat
Top picks at a glance
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Best OverallGoogle Nest Thermostat9.8 View on Amazon -
Runner-Upecobee Smart Thermostat Premium9.5 View on Amazon -
Also GreatAmazon Smart Thermostat9.5 View on Amazon -
Also GreatSensi Lite Smart Thermostat9.5 View on Amazon -
9.2 View on Amazon
Compare the specs
Ranked on works without a c-wire, room sensor support, works with alexa / google, energy star, phone app control from each listing, plus how many buyers have rated it. A dash (—) means we could not confirm that figure from the listing.
| Pick | Works without a C-wire | Room sensor support | Works with Alexa / Google | ENERGY STAR | Phone app control | Weight | Warranty |
|---|---|---|---|---|---|---|---|
| 1. Google Nest Thermostat | Yes | — | Yes | Yes | Yes | — | 1-year |
| 2. ecobee Smart Thermostat Premium | — | Yes | Yes | Yes | Yes | — | 3-year |
| 3. Amazon Smart Thermostat | — | — | Yes | — | Yes | — | — |
| 4. Sensi Lite Smart Thermostat | Yes | — | Yes | Yes | Yes | — | 3-year |
| 5. Honeywell Home T5 Smart Wi-Fi Thermostat RTH8800WF2022 | — | — | Yes | Yes | — | — | 2-year |
Google Nest Thermostat
It pairs ENERGY STAR certification with app control, operation without a C-wire in most homes and a 1-year warranty.
- Works without a C-wire
- Works with Alexa / Google
- ENERGY STAR
- Phone app control
- 1-year warranty stated
Good for
- Buyers who want operation without a C-wire
- Buyers who want an energy efficient schedule
Skip it if
- You want a warranty longer than 1 year
- You want a display larger than 2 inches
It works without a C-wire in most homes, with app control for an energy efficient schedule and remote temperature changes from anywhere. It turns itself down when you leave, and HVAC monitoring sends an alert if something seems off. The 2-inch display works with Google Assistant and Matter-certified voice assistants, and it carries a 1-year warranty.
ecobee Smart Thermostat Premium
It pairs a room sensor with an air quality monitor, app control and a 3-year warranty.
- Room sensor support
- Works with Alexa / Google
- ENERGY STAR
- Phone app control
- 3-year warranty stated
Good for
- Buyers who want a room sensor included
- Buyers who want an air quality monitor
Skip it if
- You want a warranty longer than 3 years
- You want savings above 26%
It includes a SmartSensor that detects rooms in use and adjusts temperature room by room, plus a built-in air quality monitor with alerts. The app adjusts settings from anywhere, and it carries a 3-year warranty.
Amazon Smart Thermostat
It pairs Alexa control with app control, programmable schedules and comfort zones.
- Works with Alexa / Google
- Phone app control
Good for
- Buyers who want Alexa control
- Buyers who want programmable schedules
Skip it if
- You want more than home, away and sleep schedules
- You want control without Alexa
It controls by Alexa with app control from anywhere, and it creates home, away and sleep schedules or lets Alexa control temperature automatically. Comfort zones form by connecting select Alexa devices that adjust heating and cooling by temperature or presence. Installation is do-it-yourself with guidance in the Alexa app, and it uses Honeywell Home thermostat technology.
Sensi Lite Smart Thermostat
It pairs ENERGY STAR certification with app control, operation without a C-wire in most homes and a 3-year warranty.
- Works without a C-wire
- Works with Alexa / Google
- ENERGY STAR
- Phone app control
- 3-year warranty stated
Good for
- Buyers who want geofencing control
- Buyers who want flexible scheduling
Skip it if
- You want a warranty longer than 3 years
- You want savings above 23%
It works without a C-wire in most homes, with flexible scheduling, geofencing, remote access and usage reports. It saves about 23% on HVAC energy, and the mobile app controls comfort from a smartphone or tablet. Installation is do-it-yourself with a built-in level and step-by-step instructions, and it carries a 3-year warranty.
Honeywell Home T5 Smart Wi-Fi Thermostat RTH8800WF2022
It pairs a 7-day programmable touchscreen with geofencing, auto home and away and a 2-year warranty.
- Works with Alexa / Google
- ENERGY STAR
- 2-year warranty stated
Good for
- Buyers who want 7-day scheduling
- Buyers who want geofencing control
Skip it if
- You want a warranty longer than 2 years
- You want operation without a C-wire
It offers 7-day flexible scheduling or location-based temperature control through geofencing, with auto home and away mode. Monthly energy reports track heating and cooling with personalized tips, and it is ENERGY STAR certified. A C-wire power adapter is required, and it carries a 2-year limited warranty.
How to choose
C-wire needs differ
C-wire needs differ across these thermostats. The Nest and Sensi work without a C-wire, while the ecobee includes a Power Extender Kit for homes without a C-wire. The Honeywell requires a C-wire power adapter. Check your system's compatibility before choosing.
Energy saving features
Energy saving features differ too. The Nest turns itself down when you leave and offers a Savings Finder for schedule tweaks. The Amazon creates home, away and sleep schedules for automatic control. Compare the saving features with your routine before choosing.
Controls and warranties
Controls and warranties differ as well. The Nest, ecobee, Sensi and Honeywell carry ENERGY STAR certification. The Nest, ecobee and Sensi work with Alexa and Google, and the ecobee adds Siri and a room sensor. Warranties run 1 year on the Nest, 3 years on the ecobee and Sensi, and 2 years on the Honeywell. The Amazon works with Alexa and the Alexa app for schedules and comfort zones. Check the controls and warranty length before choosing.
FAQ
Which thermostats work without a C-wire?
The Nest and Sensi work without a C-wire, and the ecobee includes a Power Extender Kit for homes without a C-wire.
Which thermostats carry ENERGY STAR certification?
The Nest, ecobee, Sensi and Honeywell carry ENERGY STAR certification for energy saving operation.
What warranties do these thermostats carry?
The Nest carries a 1-year warranty, the ecobee and Sensi carry 3-year warranties, and the Honeywell carries a 2-year warranty.
Which thermostats offer geofencing?
The Sensi and Honeywell offer geofencing for location-based temperature control based on your phone location.
