Updated:June, 2026

10 Best Heat Only Smart Thermostat No C Wire of 2026

Save up to32% Off

Best Choice

9.9

Outstanding

Emerson

Emerson Sensi Wi-Fi Smart Thermostat for Smart Home, DIY, Works With Alexa, Energy Star Certified, ST55

32% Off

Why We Love It

PRIVACY PROTECTION*: Sensi wont sell your personal information to third parties
SAVE ABOUT 23% ON HVAC ENERGY*: The ENERGY STAR-certified Sensi smart thermostat can help you save energy with features like flexible scheduling, remote access, and usage reports
EASY DIY INSTALLATION: Use the built-in level and step-by-step app instructions for a quick installation. Works with HVAC equipment found in most homes. Common wire (c-wire) is not required in most applications
SMART MAINTENANCE: Sensi can help monitor the performance and efficiency of your HVAC system by delivering valuable usage reports, alerts about your equipment, and maintenance reminders like filter replacement
SIMPLE CONFIGURATION: Looks and feels like a thermostat. Has buttons and fits the same space as a traditional thermostat so you dont have to patch and paint your walls

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Why We Love It

PRIVACY PROTECTION*: Sensi wont sell your personal information to third parties
SAVE ABOUT 23% ON HVAC ENERGY*: The ENERGY STAR-certified Sensi smart thermostat can help you save energy with features like flexible scheduling, remote access, and usage reports
EASY DIY INSTALLATION: Use the built-in level and step-by-step app instructions for a quick installation. Works with HVAC equipment found in most homes. Common wire (c-wire) is not required in most applications
SMART MAINTENANCE: Sensi can help monitor the performance and efficiency of your HVAC system by delivering valuable usage reports, alerts about your equipment, and maintenance reminders like filter replacement
SIMPLE CONFIGURATION: Looks and feels like a thermostat. Has buttons and fits the same space as a traditional thermostat so you dont have to patch and paint your walls

How We Find the Top Picks

We use smart data tools to review thousands of products and stores, analyzing ratings, reviews, and popularity trends to highlight what truly matters to shoppers like you.

Our experts then refine the results, blending AI insights with real user experiences to deliver accurate, up-to-date rankings that help you choose with confidence.

9.5

Excellent

Sensi

Sensi Lite Smart Thermostat, Programmable, WiFi, Easy DIY, Works With Alexa, ENERGY STAR Certified, ST25, Most Systems C-Wire Not Required, C-Wire needed with Heat/Cool Only & Heat Pump System – Black

8% Off

Main Highlights

EASY DIY INSTALLATION: Do it yourself fast with a built-in level and simple step-by-step instructions. Works with the HVAC equipment found in most homes
COMMON WIRE REQUIREMENTS: Common wire(C-Wire) required for heat pump and heat/cool only systems. C-wire not required on most systems
SAVE ABOUT 23% ON HVAC ENERGY*: ENERGY STAR-certified and packed with features that help you save money, including flexible scheduling, geofencing, remote access and usage reports
PRIVACY PROTECTION*: Sensi wont sell your personal information to third parties or leverage your thermostat activity data for targeting or advertising purposes
CONTROL FROM ANYWHERE: The top-rated mobile app for Android and iOS devices makes it easy to control your comfort from a smartphone or tablet

Check Price

Main Highlights

EASY DIY INSTALLATION: Do it yourself fast with a built-in level and simple step-by-step instructions. Works with the HVAC equipment found in most homes
COMMON WIRE REQUIREMENTS: Common wire(C-Wire) required for heat pump and heat/cool only systems. C-wire not required on most systems
SAVE ABOUT 23% ON HVAC ENERGY*: ENERGY STAR-certified and packed with features that help you save money, including flexible scheduling, geofencing, remote access and usage reports
PRIVACY PROTECTION*: Sensi wont sell your personal information to third parties or leverage your thermostat activity data for targeting or advertising purposes
CONTROL FROM ANYWHERE: The top-rated mobile app for Android and iOS devices makes it easy to control your comfort from a smartphone or tablet

9.5

Excellent

Sensi

Sensi Lite Smart Thermostat, Programmable, WiFi, Easy DIY, Works With Alexa, ENERGY STAR Certified, ST25W, Most Systems C-Wire Not Required, C-Wire needed with Heat/Cool Only & Heat Pump System -White

29% Off

Main Highlights

EASY DIY INSTALLATION: Do it yourself fast with a built-in level and simple step-by-step instructions. Works with the HVAC equipment found in most homes
COMMON WIRE REQUIREMENTS: Common wire(C-Wire) required for heat pump and heat/cool only systems. C-wire not required on most systems
SAVE ABOUT 23% ON HVAC ENERGY*: ENERGY STAR-certified and packed with features that help you save money, including flexible scheduling, geofencing, remote access and usage reports
PRIVACY PROTECTION*: Sensi wont sell your personal information to third parties or leverage your thermostat activity data for targeting or advertising purposes
CONTROL FROM ANYWHERE: The top-rated mobile app for Android and iOS devices makes it easy to control your comfort from a smartphone or tablet

Check Price

Main Highlights

EASY DIY INSTALLATION: Do it yourself fast with a built-in level and simple step-by-step instructions. Works with the HVAC equipment found in most homes
COMMON WIRE REQUIREMENTS: Common wire(C-Wire) required for heat pump and heat/cool only systems. C-wire not required on most systems
SAVE ABOUT 23% ON HVAC ENERGY*: ENERGY STAR-certified and packed with features that help you save money, including flexible scheduling, geofencing, remote access and usage reports
PRIVACY PROTECTION*: Sensi wont sell your personal information to third parties or leverage your thermostat activity data for targeting or advertising purposes
CONTROL FROM ANYWHERE: The top-rated mobile app for Android and iOS devices makes it easy to control your comfort from a smartphone or tablet

9.2

Excellent

Emerson

Emerson Sensi Touch Wi-Fi Smart Thermostat with Touchscreen Color Display, Works with Alexa, Energy Star Certified, C-wire Required, ST75 Black 5.625" x 3.4" x 1.17"

Main Highlights

PRIVACY PROTECTION*: Sensi wont sell your personal information to third parties
EASY DIY INSTALLATION: Use the built-in level, illuminated easy-click terminals and step-by-step app instructions for a quick installation; Works with the HVAC equipment found in most homes. Common wire (c-wire) is required
SAVE ABOUT 23% ON HVAC ENERGY*: The ENERGY STAR-certified Sensi smart thermostat can help you save energy with features like flexible scheduling, remote access and usage reports
SLEEK, MODERN DESIGN: The large color display features easy-to-read temperatures and intuitive menus. Available in black, white and silver to complement your home décor
CONTROL FROM ANYWHERE: Remotely control your home comfort from your smartphone or tablet using the Sensi mobile app for Android and iOS devices
SMART MAINTENANCE: Sensi can help monitor the performance and efficiency of your HVAC system by delivering valuable usage reports, alerts about your equipment, and maintenance reminders like filter replacement

Check Price

Main Highlights

PRIVACY PROTECTION*: Sensi wont sell your personal information to third parties
EASY DIY INSTALLATION: Use the built-in level, illuminated easy-click terminals and step-by-step app instructions for a quick installation; Works with the HVAC equipment found in most homes. Common wire (c-wire) is required
SAVE ABOUT 23% ON HVAC ENERGY*: The ENERGY STAR-certified Sensi smart thermostat can help you save energy with features like flexible scheduling, remote access and usage reports
SLEEK, MODERN DESIGN: The large color display features easy-to-read temperatures and intuitive menus. Available in black, white and silver to complement your home décor
CONTROL FROM ANYWHERE: Remotely control your home comfort from your smartphone or tablet using the Sensi mobile app for Android and iOS devices
SMART MAINTENANCE: Sensi can help monitor the performance and efficiency of your HVAC system by delivering valuable usage reports, alerts about your equipment, and maintenance reminders like filter replacement

9.0

Excellent

Amazon

Amazon Smart Thermostat – Save money and energy - Works with Alexa and Ring - C-wire required

Main Highlights

An Alexa thermostat - Amazon Smart Thermostat is an easy way to switch from a traditional thermostats for homes and help reduce energy usage.
Create comfort zones throughout your home by connecting to select Alexa devices to automatically adjust heating and cooling based on temperature readings or presence detection.
Save money and energy - After purchase, Amazon will send you an email with details about home thermostat rebates that may be available from energy providers in your area.
Save energy - According to EPA estimates, ENERGY STAR certified thermostats save an average of $50 on yearly energy bills.
Programmable thermostat and automatic control - Create your own home, away and sleep schedules, or have Alexa automatically control the temperature with Alexa+ advanced features.
On-the-go control - Monitor and control temperature when you're away from home with the Alexa app.
Do-it-yourself installation - The Alexa app will guide you through the installation process, but customer service is always available.
Reliable - Made with Honeywell Home Thermostat Technology and backed by 130 years of experience.
Create your Alexa+ home: With Alexa+, set routines using just your voice, control multiple devices at once, and chat casually to make requests.

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Main Highlights

An Alexa thermostat - Amazon Smart Thermostat is an easy way to switch from a traditional thermostats for homes and help reduce energy usage.
Create comfort zones throughout your home by connecting to select Alexa devices to automatically adjust heating and cooling based on temperature readings or presence detection.
Save money and energy - After purchase, Amazon will send you an email with details about home thermostat rebates that may be available from energy providers in your area.
Save energy - According to EPA estimates, ENERGY STAR certified thermostats save an average of $50 on yearly energy bills.
Programmable thermostat and automatic control - Create your own home, away and sleep schedules, or have Alexa automatically control the temperature with Alexa+ advanced features.
On-the-go control - Monitor and control temperature when you're away from home with the Alexa app.
Do-it-yourself installation - The Alexa app will guide you through the installation process, but customer service is always available.
Reliable - Made with Honeywell Home Thermostat Technology and backed by 130 years of experience.
Create your Alexa+ home: With Alexa+, set routines using just your voice, control multiple devices at once, and chat casually to make requests.

8.8

Very Good

ecobee

ecobee Smart Thermostat Essential - Energy Star Certified programmable Wi-Fi Thermostat - Works with Siri, Alexa, and Google Assistant

14% Off

Main Highlights

Save up to 23% every year on heating and cooling costs, adjusts to your set schedule to save energy when youre gone and optimize comfort when youre home. Compared to a hold of 72
Compatible with 85% of systems, check your systems compatibility with our online ecobee Compatibility Checker on the ecobee support page
Change your temperature by easily tapping the color touchscreen or using the ecobee app. Plus, free software upgrades ensure you get the best out of your Smart Thermostat Essential, for years to come
Automatically adjusts to your set schedule to save energy when youre gone and optimize comfort when youre home. Keep track of your energy consumption when you're on the go on the ecobee app
Easy DIY install. No C Wire, no problem. Get the ecobee Power Extender Kit (PEK) for homes without a C-Wire and keep your walls looking nice with our trim kit both sold separately
Works with leading smart home ecosystems. Pair Smart Thermostat Essential with Apple HomeKit, Google Assistant, and Alexa
Works with most 24 VAC HVAC equipment: Gas, oil, electric, dual fuel, forced air Conventional (2H/1C or 1H/2C) Heat Pump (2H/1C) Boilers. You can check your systems compatibility with our online ecobee Compatibility Checker on the ecobee support page
Add in a SmartSensor which allows you to measure the temperature in rooms that matter most. It reads temperature and movement in whatever room it is placed in for complete home monitoring and energy savings (SmartSensor 2 pack sold separately)
Built in eco+ Smart Features: Indoor humidity detection, schedule assistant, time of use which preheats or precools your home when energy is less expensive to reduce energy use during peak hours

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Main Highlights

Save up to 23% every year on heating and cooling costs, adjusts to your set schedule to save energy when youre gone and optimize comfort when youre home. Compared to a hold of 72
Compatible with 85% of systems, check your systems compatibility with our online ecobee Compatibility Checker on the ecobee support page
Change your temperature by easily tapping the color touchscreen or using the ecobee app. Plus, free software upgrades ensure you get the best out of your Smart Thermostat Essential, for years to come
Automatically adjusts to your set schedule to save energy when youre gone and optimize comfort when youre home. Keep track of your energy consumption when you're on the go on the ecobee app
Easy DIY install. No C Wire, no problem. Get the ecobee Power Extender Kit (PEK) for homes without a C-Wire and keep your walls looking nice with our trim kit both sold separately
Works with leading smart home ecosystems. Pair Smart Thermostat Essential with Apple HomeKit, Google Assistant, and Alexa
Works with most 24 VAC HVAC equipment: Gas, oil, electric, dual fuel, forced air Conventional (2H/1C or 1H/2C) Heat Pump (2H/1C) Boilers. You can check your systems compatibility with our online ecobee Compatibility Checker on the ecobee support page
Add in a SmartSensor which allows you to measure the temperature in rooms that matter most. It reads temperature and movement in whatever room it is placed in for complete home monitoring and energy savings (SmartSensor 2 pack sold separately)
Built in eco+ Smart Features: Indoor humidity detection, schedule assistant, time of use which preheats or precools your home when energy is less expensive to reduce energy use during peak hours

8.6

Very Good

Honeywell Home

Honeywell Home RTH9600WF Smart Color Thermostat ENERGY STAR Wi-Fi Programmable Touchscreen Alexa Ready - C-Wire Required

26% Off

Main Highlights

ENERGY STAR certified to help save energy, track your heating and cooling and send personalized tips on reducing energy use..Includes : Thermostat, Wall Plate, Screws, Anchors, Quick Start Guide, Thermostat ID Card, Wire Labels, User Guide
SAVE ENERGY AND GET REWARDED by checking with your energy provider about available energy savings rebates to save on your purchase (rebate finder link above). Plus, eligible customers can enroll in ongoing energy savings incentives with their energy provider to keep saving all year long.
CONTROL FROM ANYWHERE by using the app or compatible smart home partners including AMAZON ALEXA, GOOGLE ASSISTANT, MICROSOFT CORTANA, and more. Flexible programming options are also available if you'd rather set it and forget it but still benefit from energy savings.
CUSTOMIZABLE COLOR SCREEN: Easily change the high-definition display of the Wi-Fi thermostat to any color you choose.
ON-SCREEN COMFORT INFORMATION: See indoor and outdoor temperature and humidity information right on the home screen, plus daily weather forecast available on the smart thermostat.
COMPATIBLE WITH: Forced air (gas, oil or electric), hot water and steam, and heat pumps with electric backup. Does NOT work with electric baseboard heat (120-240V). C-WIRE REQUIRED. Before purchasing, check to see if this smart programmable thermostat is compatible with your home and to determine if your home needs a C-wire power adapter.
C-WIRE POWER ADAPTER REQUIRED: Before purchasing, check to see if this thermostat is compatible with your home and to determine if your home needs a C-wire power adapter.
Includes : Thermostat, Wall Plate, Screws, Anchors, Quick Start Guide, Thermostat ID Card, Wire Labels, User Guide
Works with most heat/cool oil furnace systems. Will not work with heating only oil furnace systems unless a C-Wire is present.

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Main Highlights

ENERGY STAR certified to help save energy, track your heating and cooling and send personalized tips on reducing energy use..Includes : Thermostat, Wall Plate, Screws, Anchors, Quick Start Guide, Thermostat ID Card, Wire Labels, User Guide
SAVE ENERGY AND GET REWARDED by checking with your energy provider about available energy savings rebates to save on your purchase (rebate finder link above). Plus, eligible customers can enroll in ongoing energy savings incentives with their energy provider to keep saving all year long.
CONTROL FROM ANYWHERE by using the app or compatible smart home partners including AMAZON ALEXA, GOOGLE ASSISTANT, MICROSOFT CORTANA, and more. Flexible programming options are also available if you'd rather set it and forget it but still benefit from energy savings.
CUSTOMIZABLE COLOR SCREEN: Easily change the high-definition display of the Wi-Fi thermostat to any color you choose.
ON-SCREEN COMFORT INFORMATION: See indoor and outdoor temperature and humidity information right on the home screen, plus daily weather forecast available on the smart thermostat.
COMPATIBLE WITH: Forced air (gas, oil or electric), hot water and steam, and heat pumps with electric backup. Does NOT work with electric baseboard heat (120-240V). C-WIRE REQUIRED. Before purchasing, check to see if this smart programmable thermostat is compatible with your home and to determine if your home needs a C-wire power adapter.
C-WIRE POWER ADAPTER REQUIRED: Before purchasing, check to see if this thermostat is compatible with your home and to determine if your home needs a C-wire power adapter.
Includes : Thermostat, Wall Plate, Screws, Anchors, Quick Start Guide, Thermostat ID Card, Wire Labels, User Guide
Works with most heat/cool oil furnace systems. Will not work with heating only oil furnace systems unless a C-Wire is present.

8.3

Very Good

YABUYALI

Upgraded C-Wire Adapter Stable Connection for Smart Thermostats, Reinforced Common Wire Adapter for Long Term Thermostat Use THP9045A2098/U

Main Highlights

Core Functionality: As a c wire adapter, it is designed specifically for smart thermostats without a C-wire (common wire). It can convert G and Y wires into C and K wires, providing stable power supply for smart thermostat no c wire and solving the power supply problem of smart thermostats without a C-wire.
Device Compatibility: It is compatible with Honeywell home series smart thermostat. It is an excellent choice c wire adapter for smart thermostat and can also be used as an alternative to the nest c wire power adapter
Easy Installation: Follow the step-by-step installation guide, from powering off, labeling the wires, to connecting the adapter to the HVAC system. The operation process is clear, and even users who are not familiar with thermostat wiring can easily complete the installation of the c wire adapter for thermostat and realize the intelligent upgrade of thermostat without c wire
Wide Application Scenarios: It is suitable for various wifi thermostats without a C-wire (such as smart wifi thermostats without a C-wire), covering mainstream brands . It is a key accessory for no c-wire smart thermostat to achieve stable operation
Technical Value: As a c wire power adapter, it acts as a thermostat adapter interface between the thermostat and the HVAC system. Through wire conversion technology, it enables traditional thermostat wiring without a C-wire to support the power supply requirements of smart thermostats, making it a practical technical accessory in the era of smart thermostat no c wire

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Main Highlights

Core Functionality: As a c wire adapter, it is designed specifically for smart thermostats without a C-wire (common wire). It can convert G and Y wires into C and K wires, providing stable power supply for smart thermostat no c wire and solving the power supply problem of smart thermostats without a C-wire.
Device Compatibility: It is compatible with Honeywell home series smart thermostat. It is an excellent choice c wire adapter for smart thermostat and can also be used as an alternative to the nest c wire power adapter
Easy Installation: Follow the step-by-step installation guide, from powering off, labeling the wires, to connecting the adapter to the HVAC system. The operation process is clear, and even users who are not familiar with thermostat wiring can easily complete the installation of the c wire adapter for thermostat and realize the intelligent upgrade of thermostat without c wire
Wide Application Scenarios: It is suitable for various wifi thermostats without a C-wire (such as smart wifi thermostats without a C-wire), covering mainstream brands . It is a key accessory for no c-wire smart thermostat to achieve stable operation
Technical Value: As a c wire power adapter, it acts as a thermostat adapter interface between the thermostat and the HVAC system. Through wire conversion technology, it enables traditional thermostat wiring without a C-wire to support the power supply requirements of smart thermostats, making it a practical technical accessory in the era of smart thermostat no c wire

8.1

Very Good

ecobee

ecobee Smart Thermostat Enhanced - Programmable Wifi Thermostat - Works with Siri, Alexa, Google Assistant - Energy Star Certified - Smart Home

15% Off

Main Highlights

Save up to 26% per year on heating and cooling costs Automatically adjusts the temperature when youre away to never heat or cool an empty home. Compared to a hold of 72°F
Compatible with 90% of systems so check your systems compatibility with our Compatibility Checker on the ecobee support page. The Power Extender Kit (PEK) and Trim Kit is included in the box with everything else youll need for an easy DIY install.
Built-in radar occupancy preheats or precools your home before you arrive so its the perfect temperature the moment you walk in. Automatically adjusts to your desired temperature when youre home or sleeping to keep you comfortable day and night.
Learns your temperature preferences and your schedule so your home is just the way you like it and automatically adjusts based on humidity.
Use your smart home platform and the ecobee app to control your thermostat from anywhere with your smartphone, tablet, or Apple Watch.
Add ecobee SmartSensors which will detect which rooms are in use and adjust the temperature accordingly.
Works with most 24 VAC HVAC equipment: Gas, oil, electric, dual fuel, forced air Conventional (2H/2C) Heat Pump (3H/2C), & Boilers. Includes Power Extender Kit for homes without a C or Common Wire, to ensure an easy installation
Hardwired so you never have to worry about losing control or replacing batteries. Compatible with 90% of systems.

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Main Highlights

Save up to 26% per year on heating and cooling costs Automatically adjusts the temperature when youre away to never heat or cool an empty home. Compared to a hold of 72°F
Compatible with 90% of systems so check your systems compatibility with our Compatibility Checker on the ecobee support page. The Power Extender Kit (PEK) and Trim Kit is included in the box with everything else youll need for an easy DIY install.
Built-in radar occupancy preheats or precools your home before you arrive so its the perfect temperature the moment you walk in. Automatically adjusts to your desired temperature when youre home or sleeping to keep you comfortable day and night.
Learns your temperature preferences and your schedule so your home is just the way you like it and automatically adjusts based on humidity.
Use your smart home platform and the ecobee app to control your thermostat from anywhere with your smartphone, tablet, or Apple Watch.
Add ecobee SmartSensors which will detect which rooms are in use and adjust the temperature accordingly.
Works with most 24 VAC HVAC equipment: Gas, oil, electric, dual fuel, forced air Conventional (2H/2C) Heat Pump (3H/2C), & Boilers. Includes Power Extender Kit for homes without a C or Common Wire, to ensure an easy installation
Hardwired so you never have to worry about losing control or replacing batteries. Compatible with 90% of systems.

8.1

Very Good

Honeywell Home

Honeywell Home RTH8800WF2022, T5 WiFi Smart Thermostat, 7 Day-Programmable Touchscreen, Alexa Ready, Geofencing Technology, Energy Star, C-Wire Required

13% Off

Main Highlights

High use of the scheduling feature of the T5 thermostat saved customers between 8 and 16% on heating and cooling bills. Dollar savings range based on nationwide average annual single-family detached home's heat and cooling bills; actual savings varies based on consumption.
Save Energy and Get Rewarded. Check with your energy provider about available energy savings rebates to save on your purchase. Plus, eligible customers can enroll in their local Utility's "DEMAND RESPONSE PROGRAM" which can reward you for allowing the utility to slightly adjust your AC or furnace temperature settings when there is high energy demand.
7-Day Flexible Scheduling or Location Based Temperature Control. Its your choice. 7-day scheduling programs your thermostat. Geofence technology helps make you comfortable by using your smartphones location to know when youre away and when you return.
Auto Home and Away Mode. Enjoy ideal temperatures at home, then save when away.
ENERGY STAR certified. Help save energy, track your heating and cooling with monthly energy reports and get personalized tips on reducing energy use.
C-WIRE POWER ADAPTER REQUIRED: Before purchasing, check to see if this thermostat is compatible with your home and to determine if your home needs a C-wire power adapter.
Works with most heat/cool oil furnace systems. Will not work with heating only oil furnace systems unless a C-Wire is present.
The T5 thermostat is ENERGY STAR certified and you can program it based on your schedule, or let it adapt to your life as plans change

Check Price

Main Highlights

High use of the scheduling feature of the T5 thermostat saved customers between 8 and 16% on heating and cooling bills. Dollar savings range based on nationwide average annual single-family detached home's heat and cooling bills; actual savings varies based on consumption.
Save Energy and Get Rewarded. Check with your energy provider about available energy savings rebates to save on your purchase. Plus, eligible customers can enroll in their local Utility's "DEMAND RESPONSE PROGRAM" which can reward you for allowing the utility to slightly adjust your AC or furnace temperature settings when there is high energy demand.
7-Day Flexible Scheduling or Location Based Temperature Control. Its your choice. 7-day scheduling programs your thermostat. Geofence technology helps make you comfortable by using your smartphones location to know when youre away and when you return.
Auto Home and Away Mode. Enjoy ideal temperatures at home, then save when away.
ENERGY STAR certified. Help save energy, track your heating and cooling with monthly energy reports and get personalized tips on reducing energy use.
C-WIRE POWER ADAPTER REQUIRED: Before purchasing, check to see if this thermostat is compatible with your home and to determine if your home needs a C-wire power adapter.
Works with most heat/cool oil furnace systems. Will not work with heating only oil furnace systems unless a C-Wire is present.
The T5 thermostat is ENERGY STAR certified and you can program it based on your schedule, or let it adapt to your life as plans change

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