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To install an Amazon Smart Thermostat, first confirm your HVAC system is compatible and has a usable C wire or an approved adapter. Then switch off HVAC power, photograph and label the existing wiring, follow the Alexa app’s wiring guide, and restore power only after the thermostat is mounted and connected. Stop and call an HVAC professional if you see high-voltage wiring, cannot identify the wires, or are unsure about the work.
Check whether your HVAC system is compatible
Use Amazon’s compatibility checker before buying or starting installation. Amazon says the thermostat supports air-to-air and geothermal heat pumps, but not heat pumps with a backup gas or oil furnace. It requires a C (common) wire for power, though an adapter may be an option if your system does not have a usable one.
Do not install it on a high-voltage system. Amazon says to stop if you see labels such as 110 V or 220 V, L1/L2 wiring, or wires joined with wire nuts. These are signs the system may not be the low-voltage type the thermostat is designed for. If the wiring is unclear, have an HVAC professional assess it.
Check for a C wire before removing the old thermostat
A C wire supplies continuous power to the thermostat. With the old thermostat still in place, check whether a wire is connected to the terminal marked C. Do not identify wires by color alone; use terminal labels and the Alexa app’s instructions.
#1 Best Overall
- 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 $90 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.
- C wire is connected: Photograph the wiring and label each wire by the terminal it is connected to.
- No C wire is connected: There may be an unused conductor behind the thermostat that can be connected to C at both the thermostat and the HVAC control panel. If there is no usable conductor, a compatible C-wire adapter may be needed.
Installing an adapter involves work at the HVAC control board. Follow Amazon’s adapter instructions and turn off power before opening or working at the control panel. If you cannot confidently identify the terminals or wiring, use an HVAC service company.
Turn off power and document the existing wiring
- Switch off power to the HVAC system at its breaker or primary switch. Verify the system is off before touching the thermostat or wires.
- Remove the old thermostat faceplate. Photograph the terminals and connected wires so you can refer to the original setup.
- Label each wire with the name of the terminal it came from, then disconnect it. Keep wires from slipping back into the wall, and do not touch exposed wire ends.
If wires are too short, disappear into the wall, or do not match the app’s wiring guidance, stop rather than guessing. Amazon recommends contacting an HVAC service company if you are not comfortable working with the wiring or heating and cooling system.
Rank #2
- The information below is per-pack only
- 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.
Mount and wire the Amazon Smart Thermostat
- Remove the old wall plate. Install the optional trim plate if you want to cover marks or gaps around the thermostat.
- Fasten the Amazon thermostat wall plate to the wall.
- Open the Alexa app and follow its illustrated wiring instructions. Insert each labeled wire into the slot shown for its original terminal; do not rely on wire color.
- Gently tug each wire to check that it is held securely. Check the R terminal switch position as directed in the app.
- Close the thermostat cover and attach the faceplate. Once the wiring and mounting are complete, restore HVAC power.
Complete setup in the Alexa app
In the Alexa app, select Devices > Add Device > Thermostat > Amazon. Choose No if the thermostat is not installed yet to open the wiring and installation guidance. Choose Yes if it is already mounted and you are ready for Wi-Fi and Alexa setup.
Amazon says the display showing “SEt” or a temperature indicates successful installation. The thermostat requires a 2.4 GHz Wi-Fi network; 5 GHz Wi-Fi is not compatible.
Rank #3
- Like-New Amazon Smart Thermostat is refurbished, tested, and certified to look and work like new and comes with the same limited warranty as a new device. Like-New Amazon devices may be packaged in generic Amazon-branded boxes.
- Smart upgrade - Amazon Smart Thermostat is an easy way to switch from a traditional thermostat and help reduce energy usage.
- Create comfort zones throughout your home by using select Echo devices or Amazon Smart Air Quality Monitor to automatically adjust heating and cooling based on temperature readings or presence detection.
- Save money - After purchase, Amazon will send you an email with details about rebates that may be available from energy providers in your area. Explore rebates above.
- Save energy - According to EPA estimates, ENERGY STAR certified thermostats save an average of $50 on yearly energy bills.
When to stop and call a professional
- The system has 110 V or 220 V labels, L1/L2 wiring, or wires joined by wire nuts.
- Your system is unsupported, including a heat pump with backup gas or oil heat.
- You cannot identify a terminal or wire from its label and the app’s instructions, or wires are too short or have slipped into the wall.
- You need to work at the HVAC control board to install an adapter and are not confident doing so safely.
- You are uncomfortable with HVAC wiring, or local rules require a qualified professional or permit.
Amazon’s official wiring instructions advise: “If you are not comfortable working with electrical wiring or your home heating and cooling system, contact a HVAC service company to install and set up your Thermostat.”
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.Amazon Smart Thermostat electrical rating
Amazon’s safety and compliance page identifies model S6ED3R and lists an electrical rating of 24 V, 60 Hz, 0.2 A on a Class 2 circuit. This is the thermostat’s listed rating, not permission to connect it to a household high-voltage system.
Quick Recap
Best Value
- Save up to 23% every year on heating and cooling costs, adjusts to your set schedule to save energy when you’re gone and optimize comfort when you’re home. Compared to a hold of 72
- Compatible with 85% of systems, check your system’s 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 you’re gone and optimize comfort when you’re 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
Rank #4
- 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 won’t 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
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
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