Best Smart Thermostat Without C Wire

Smart Thermostat without c wire

I had just upgraded my HVAC system, switching over to gas. It would be the best time to upgrade all the house’s thermostats to smart ones. A little excited, i got the HVAC company to inspect our thermostat wires, and we only had three, a red wire, a white wire, and a green wire. This means we did not have a Common or C wire, and to rewire the house would cost two thousand dollars for three thermostats. Most smart thermostats require a c wire, so I had to find a solution.

After extensive research, I’ve found a few smart thermostats without c wire available. Not only that, the best smart thermostats without a c wire cost a fraction of the cost of a re-wiring job from your HVAC Company. Keep reading to find out your options.

You can find smart thermostats without a C-wire that control your HVAC system just as efficiently. These smart thermostats are perfect for homes with old wiring whose HVACs may need a C-wire. In this case, your thermostat will either be battery-operated or pull power from your furnace or boiler since your HVAC has no common wire to supply 24 volts of AC power.

I have reviewed two thermostats without the C-wire requirement. They are easy to install and works well with your smart home assistants such as Alexa and google assistant.

What Smart Thermostats Require No C-Wire?

Here are smart thermostats that work best for your home if your HVAC has no common wire:

1. The Emerson Sensi Wi-Fi Smart Thermostat

thermostat without c wirethermostat without c wire

Right out of the box, I noticed Sensi smart thermostat features a traditional footprint that makes it ideal for old homes. While most smart thermostats require you to patch your wall or paint during installation, this smart thermostat will install on the same footprint as a traditional thermostat. Of course, this makes it an easy DIY install!

I also love that this unit requires no C-wire, as it can also use batteries. And this simplifies installation even further. It can use a C-wire if your HVAC system has it, making it a versatile device.

But its smart features are what made me love it so much. To begin with, it features built-in Wi-Fi connectivity. That means I can connect it to my home Wi-Fi network and control it remotely via the Sensi app. However, I discovered that this smart thermostat connects only to Wi-Fi 2.4GHz frequency, which is common for most smart devices nowadays. But I’ve not had issues with the connectivity since my home wireless network is stable for the most part.

The Sensi app offers privacy and doesn’t sell my personal information to third parties. What’s more, it has step-by-step instructions to follow for quick Sensi smart thermostat installation. I can always control this smart thermostat on the go. It allows me to set, change, and program the smart thermostat to control the temperature how I like it.

Besides monitoring and controlling the temperature, Sensi smart thermostat also monitors the humidity. And it displays the data on its screen and lets me know what’s happening in the app. Then I can adjust the settings to keep the temperature and humidity within acceptable levels.

The smart alerts I receive via email let me know if something has plagued the heating and cooling system. That gives me time to service any damaged part of the HVAC. Sensi smart thermostats also monitor your monthly energy usage and display the reports via the Sensi app.

I also get the same report sent to my email to ensure I get my monthly energy usage. Since I own a voice assistant, I can pair my Sensi smart thermostat with a virtual assistant for hands-free control. The smart thermostat works with Alexa, Google Assistant, Apple HomeKit, and Smartthings.

If you have an older home and want to use smart technology to control your heating and cooling, a Sensi smart thermostat will help you.

Smart temperature controlSupport Only 2.5 GHz Wi-Fi connectivity
Easy DIY installBatteries not Included
Humidity monitor
Supports voice assistants
Privacy protection

2. Google Nest Learning Thermostat

thermostat without c wirethermostat without c wire

Google Nest Learning 3rd Generation is another smart thermostat I like because it’s an easy install. I can install it in 30 minutes. But many people install it in less time. To add icing to the cake, it is a beautiful thermostat boasting a polished metal finish. The stainless steel finish makes it complements any home décor. But if stainless steel isn’t your style, you can choose from mirror black, Brass, White, and Copper finishes.

I couldn’t help but notice the high-resolution color display on the Nest Learning smart thermostat. It is a stunning display that lights up in the dark when I walk across the room. And I can read the temperature displayed on the screen without lifting a finger.

Besides displaying the temperature setting, the screen also shows the weather and time. Therefore, this is a versatile smart thermostat for your home. I also noticed the green leaf displayed when I put the smart thermometer on the energy-efficient setting or eco mode.

Although this thermostat promises energy saving, external factors such as weather outside plays a significant factor in the outcome. But I still love how it goes the extra mile to keep the monthly energy usage down. And that’s true because this smart thermostat has sensors that check if you’ve left the room. Then the thermostat switches off the HVAC to conserve energy. Specifically, the smart thermostat sets itself to an Eco Mode for reduced energy usage. 

I also love that this device is compatible with over 95% of 24V HVAC systems. And this makes it ideal for any home. The smart learning feature knows your preferred temperature settings and controls the HVAC to achieve the preferred temperatures. 

I only have to use it for a week, and this device adapts to my life. With its Wi-Fi connectivity, I can connect it to my wireless home network to control it remotely via the Nest app. Also, this connectivity allows me to pair it with my voice assistant device for hands-free control.

It works best with Google Assistant, even though Amazon Alexa does an incredible job. Its connection to the Wi-Fi is seamless as it’s a dual-band smart thermostat. That makes its connection more secure for efficient remote control via the mobile app.

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At the same time, it features Bluetooth Low Energy (BLE) connectivity for pairing with your favorite voice assistants. Once I connect this smart thermostat to my internet connection, it sends notifications to my app if my HVAC has issues. But receiving the notifications depends on Internet connectivity. So, you want to ensure your internet connection is functional.

NOTE:  Nest E Learning thermostat is discontinued

The Nest E Learning thermostat also performed exceptionally and works wihout a c wire. But the company discontinued it from the google nest thermostat lineup. You should still be able to purchase it from third parties. Google Nest Learning thermostats are great, especially with their Home/Away Assist, which reduces energy consumption. I recommend these smart thermostats if you want to spend less time programming your temperature control device.


Wi-Fi and Bluetooth connectivity

Pricey when compared with other thermostats but saves you money from re-wiring your thermostat

Easy DIY install


95% HVAC systems compatibility

High-quality construction

How To Pick the Best Smart Thermostat Without a C-Wire

Whenever I buy any smart home device, I like to check if it has essential features that I need. And smart thermostats are no exception. So, here are a few things to look for before buying a smart thermostat:

The Power Source

You can power a smart thermostat in one of two ways: through a C-wire or batteries. If your HVAC system has a C-wire, you can connect its wire to the thermostat. Usually, the C-wire supplies 24V AC power that your smart thermostat relies on to work. But not all HVACs have a C-wire to power a smart thermostat.

That’s when a battery-powered operated thermostat or a smart thermostat without a c wire comes in handy.

Wireless Connectivity

2.4 ghz wifi

Smart thermostats give the convenience of controlling your indoor climate remotely. Also, they allow you to pair them with a voice assistant and control them through voice commands. These are the benefits I like about smart thermostats. But these benefits rely on wireless connectivity.

First, ensure your preferred smart thermostat has built-in Wi-Fi connectivity. I find dual-band smart thermostats more convenient since they connect to two Wi-Fi frequencies, 2.4 and 5GHz, for reliable internet connection and remote control.

But even smart thermostats connected only to Wi-Fi 2.4GHz give you efficient remote control via a mobile app. And they’re just as efficient at controlling your indoor climate from your smartphone. Aside from Wi-Fi connectivity, check to see if your smart thermostat has Bluetooth connectivity.

Bluetooth Low Energy (BLE) is great connectivity, especially if you want to conserve energy. It allows you to pair a smart thermostat with a voice assistant device such as Amazon Echo Dot for hands-free control. As a result, you will set the temperature by the sound of your voice. Therefore, opt for a smart thermostat with these wireless connectivities.

Auto-Schedule Feature

thermostat without c wire

Google Nest Learning smart thermostat has a feature called Auto-Schedule that adjusts the indoor temperature based on your settings. Once you use it for a week, it programs itself according to your desired temperature settings. I like this feature because I don’t have to set the temperature every time.

When buying a smart thermostat, check if it has this feature or similar technology. It makes using a thermostat easy. While the Nest Learning thermostat has the Auto-Schedule feature, the Sensi Wi-Fi thermostat has the Home/Away feature that works similarly.

The smart thermostat detects if you’re in the room and keeps the temperature at your desired setting. Once you leave the room, it shuts off the HVAC system to conserve energy. Both Auto-Schedule and Home/Away features aim to reduce your monthly energy usage. Therefore, you want to buy a smart thermostat with these features.

Humidity Monitoring

thermostat without c wire

I like a versatile smart thermostat that does more than monitor and controls my indoor temperature. Some smart thermostats can monitor the humidity level inside your home. What’s more, they can deliver the reports to your email and the mobile app.

You want to check the humidity level in your home since high humidity allows mods to grow rapidly. If your smart thermostat can monitor the vapor content of the indoor air, it allows you to keep humidity in check. Therefore, buy a smart thermostat capable of monitoring the humidity in your home.

Energy Consumption Report

Although not a feature, an energy consumption report is something you want from a smart thermostat. It lets you track your monthly energy consumption to better program the thermostat. The smart thermostat can send the energy consumption report to your email or smartphone via the mobile app. Therefore, look for a smart thermostat with an energy consumption report.

Ease of Installation

I like a smart thermostat I can install on my wall in 30 minutes. Fortunately, many smart thermostats I’ve been fortunate to use are easy to install. A smart thermostat such as Sensi Wi-Fi installs in the same footprint as a traditional thermostat. And this makes installation take a little less than 30 minutes.

Even if a smart thermostat doesn’t sit on the same mounting plate (or wall plate), ensure it is still easy to install on a wall. These devices are generally easy to install. But some are easier to install.

The Design

Finally, I like to check the design of a smart thermostat before buying it. This is the first time I’ve come across a smart thermostat with an unattractive design. But some designs are better looking. When checking the design, I check the display and construction material.

If the mirrored display has a high resolution to allow me to read the temperature setting from across the room, I will choose that smart thermostat. Also, I love colored displays for easy usage. But your taste may differ from mine, and that’s okay.

I also love smart thermostats constructed from high-quality materials such as stainless steel for durability. If the construction quality is high, I recommend you choose that smart thermostat because it will last for extended periods.


A smart thermostat without a C-wire is an ideal choice for older homes whose HVAC may lack a C-wire.

Check for the best features when choosing a smart thermostat for your home. One crucial factor is smart temperature control. Smart thermostats use Auto-Schedule, and Home/Away features to guarantee smart temperature control.

Also, you will check the ease of installation, these Emerson Sensi and Google nest thermostats are both DIY friendly. I’ve shared some crucial things to consider when shopping for a smart thermostat without a C-wire. I hope you’ve found this helpful in your journey to purchasing a smart thermostat.

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