Smart thermostats are incredibly convenient, allowing people to automate their home's heating and cooling system.
The ability to connect your home's thermostat to a Wi-Fi connection means you can control your smart thermostat from anywhere, even if you aren't at home. This not only allows you to schedule the right temperature for your environment but also helps you save costs on your energy bill. It's the perfect way to start building a smart home as many smart thermostats offer integration with other products like locks, cameras, and more.
When looking for the best smart thermostats, it's important to understand whether you need to purchase a smart thermostat with or without a C wire.
What Is a C Wire?
The C wire (common wire) powers a smart thermostat by providing a constant flow of 24 VAC (volts AC).
The term "constant flow" is the key here, because the C wire isn't the source of power. The R wires are the actual source of power, but they are not continuous, hence the use of the C wire.
However, not all home wiring consists of a C wire. The good news is, some of the best smart thermostats do not require the power from the C wire to work.
In fact, some of the best smart thermostats like the Google Nest Thermostat have no requirement for the C wire as they contain rechargeable batteries or other technology that removes the need for one. Here's a look at some of the best.
1. Google Nest Thermostat
Google's Nest Thermostat is a simple smart thermostat that uses a rechargeable lithium-ion battery. This bypasses the need for the C wire, offering an always-on display that details the current temperature setting.
Compatible with most voice assistants like Google Assistant and Amazon Alexa, the Google Nest Thermostat can be adjusted easily using voice commands, or via the handy smartphone app.
From one simple dashboard, you can see how much energy you've saved, invite other family members to control the smart thermostat, and set temperature schedules in each of your rooms.
Best of all, the Google Nest Thermostat is incredibly easy to install and is one of the most versatile Wi-Fi thermostats with no C wire.
Google Nest Thermostat E
8.6/ 10
TheGoogle Nest Thermostat E uses a rechargeable battery to bypass the requirement of a C wire.
It's compatible with most voice assistants and easy to use.
Pros
- Simple to use
- More affordable than the Nest Learning thermostat
- No C wire required
Cons
- Lacks more advanced features that the Nest Learning thermostat has
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2. ecobee Lite SmartThermostat
If you're searching for a smart thermostat that you can install without a C wire, on a budget, the ecobee Lite SmartThermostat is a wise choice.
While it doesn't feature all of the bells and whistles the latest generation ecobee does, it still allows you to control your heating and cooling directly from the app. This means you can schedule programs efficiently.
The ecobee Lite SmartThermostat ships with a Power Extender Kit that allows you to bypass the C wire requirement.
Aside from controlling your HVAC system, this smart thermostat is small and easy to install, making it a great option if you want to install a smart thermostat without a C wire.
ecobee Lite SmartThermostat
9.2/ 10
Theecobee Lite SmartThermostat is a budget-friendly smart thermostat that works with Amazon Alexa.
It comes with a Power Extender Kit included which allows you to bypass any requirement for a C wire.
Pros
- Affordable
- Includes Power Extender Kit to bypass C wire
- Controls heating and cooling
Cons
- Not very feature-rich
3. Google Nest Learning Thermostat
Google's Nest Learning Thermostat is one of the most popular smart thermostats, and for good reason. It's a fully programmable thermostat that boasts voice controls, compatible with Alexa, and comes in a range of designs.
One of the added benefits of opting for the Google Nest Learning Thermostat is that it can be installed with or without a C wire. So if you move homes, you'll have both options available.
A word of caution, however, is that some users may experience issues with their HVAC systems due to the smart thermostat taking power from the furnace control circuits to charge up the internal battery.
In most cases, this won't be an issue, and you'll be able to enjoy your feature-rich smart thermostat without a C wire.
Google Nest Learning Thermostat
9/ 10
$190 $249 Save $59
Keep costs down with the Google Nest Learning Thermostat which programs itself to the right temperature for your home.
Using the smart thermostat or the Nest app, you can control your heating and cooling, create schedules, and activate features like Home/Away assist.
Pros
- Plenty of advanced features
- Can detect when you're not at home and adjust the heating accordingly
- Learns from your routine
Cons
- Expensive
$190 at Amazon
4. Sensibo Sky
For those that don't have a central heating system or want to control just their AC units, the Sensibo Sky is an excellent smart air conditioner system.
With quick and easy installation, the Sensibo Sky doesn't require a C wire to be able to control your AC units. You can connect the smart system via Wi-Fi to control it via the smartphone app.
Alternatively, use voice assistants like Apple's Siri, Google, and Amazon Alexa to control your home's temperature.
By leveraging the Sensibo Sky's smart features, you can save energy and reduce your bills with scheduling and geo-fencing.
Sensibo Sky
8.6/ 10
The Sensibo Sky is an affordable option for users without a central heating or cooling system.
This smart air conditioner system works with Google Assistant, Amazon Alexa, and Siri.
Pros
- Budget-friendly
- Quick installation
- Connects with many voice assistants
Cons
- No central heating control
5. Lux GEO-WH Wi-Fi Thermostat
While not the most stylish smart thermostat, the Lux GEO-WH Wi-Fi Thermostat is a safe bet if you've tried other smart thermostats without a C wire that aren't compatible with your heating system.
It can be powered via two AA batteries, micro-USB, or C wire. This gives you multiple options, making the process far more straightforward, and easy to install.
You can program your Lux GEO-WH Wi-Fi Thermostat via the unit or through the app with a Wi-Fi connection.
The only scenario where you would need a C wire for this smart thermostat is if you wanted to use its Alexa voice control capabilities.
Lux GEO-WH Wi-Fi Thermostat
6/ 10
This affordable smart thermostat works with Amazon Alexa and is compatible with many systems.
Powered by AA batteries, theLux GEO-WH Wi-Fi Thermostat doesn't require a C wire.
Pros
- Easy to install
- Can be powered multiple ways
- Controllable via the unit or app
Cons
- Alexa voice control requires a C wire
6. Emerson Sensi
One of the most affordable smart thermostats you can install without a C wire is the Emerson Sensi Wi-Fi Smart Thermostat. It works with Alexa and boasts DIY installation.
For most applications, the C wire isn't required. You'll only need a C wire if you have a heat or cool-only system, heat pump, or you want to use Apple HomeKit.
Using Wi-Fi connectivity, the Emerson Sensi's dated style can easily be overlooked in favor of its easy controls, allowing you to program your home's heating from anywhere.
It's compatible with iOS and Android and displays usage reports so you can keep on top of your energy usage.
Emerson Sensi
9/ 10
The Emerson Sensi can be installed at home without professional help. It offers easy controls and works with Amazon Alexa.
To further save on your energy bills, you can use the iOS or Android app to monitor usage and view energy reports.
Pros
- DIY installation
- Amazon Alexa compatible
- Produces energy usage reports
Cons
- Apple HomeKit requires C wire
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7. Mysa Thermostat
The Mysa Smart Thermostat stands out due to its mid-range price and its stylish design. This line voltage thermostat has been designed to work with line voltage heating systems like baseboard heaters, fan-forced heaters, and convectors.
A C wire is not required for installation, and, once installed, the Mysa Smart Thermostat boasts a good range of features, despite little information being displayed on the panel itself.
Built-in, there are humidity and temperature sensors; when connected to a smart hub, it can sense the outside temperature and adjust your heating accordingly. There are also scheduling functions, routines the thermostat can learn, and geofencing.
This smart thermostat is easy to install in a matter of minutes. And, as well as being able to control your heating via the app, it's compatible with Alexa, Google Assistant, and Apple HomeKit too.
Mysa SmartThermostat
9/ 10
The Mysa Thermostat is reasonably priced and boasts a stylish and modern design.
It's a feature-rich smart thermostat that works with Amazon Alexa and Google Assistant.
Pros
- Stylish and modern design
- Feature-rich
- Works with line voltage heating systems
Cons
- Design means limited information is displayed
8. Wyze Smart Thermostat
Like the Google Nest Learning Thermostat, the Wyze Smart Thermostat can be installed with or without a C wire. As it isn't battery-powered, a C wire would usually replace the power. However, without a C wire, you can use the power adapter that's included.
This thermostat works with the majority of heating systems, but you can use Wyze's Thermostat Compatibility Checker to be sure your system is compatible.
Using the app, you can control the Wyze Smart Thermostat wherever you are. This includes 7-day scheduling, home/sleep/away modes, usage tracking, and more. And, if you're away from home and have a guest housesitting for you, you can share the control with your guests through the Wyze app.
Thanks to the built-in motion sensor, this smart thermostat can be programmed to automatically turn on or off. Similarly, it can use your phone's location to detect if you're not at home.
Wyze Smart Thermostat
8.2/ 10
TheWyze Smart Thermostat works with a wide range of heating systems. You can control the device using the app, no matter where you are.
From scheduling to energy usage tracking, you can retrieve useful information to save on your energy bills.
Pros
- Affordable
- Compatibility checker before purchase
- Plenty of modes
Cons
- Not compatible with Apple HomeKit
9. Honeywell Home T9
The Honeywell Home T9 smart thermostat can work with or without a C wire. Similar to the Wyze Smart Thermostat, the T9 comes with a C wire power adapter that you can use in replacement of a C wire.
Compatible with room sensors that detect the temperature of each room, this smart thermostat can respond automatically to your schedule. You will be able to see each room's temperature and humidity, which you can see in the mobile app.
If you like to stay on top of the energy you're using, you'll get a monthly energy report along with tips on how to reduce your energy usage.
And although the Honeywell Home T9 is at the upper end of the price scale, it is incredibly useful and a long-term investment for your home. Plus, it's compatible with Alexa, Google Assistant, and Apple HomeKit, so you can say "Alexa, set the temperature to 72".
Honeywell Home T9
9/ 10
TheHoneywell Home T9 has plenty of features that allow you to stay on top of your energy usage.
You can use it with or without a C wire, using the included power adapter.
Pros
- Includes C wire power adapter
- Compatible with room sensors
- Monthly energy reports
Cons
- Expensive
No C Wire—No Problem
Buying a smart thermostat that doesn't require a C wire for installation doesn't mean you're in for a poor experience.
In fact, some of the most advanced and popular smart thermostats like the Google Nest Learning Thermostat are among those that can be installed without a C wire.
Now it's easier than ever to keep an eye on your spending and control your energy usage using smart technology.
