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Modernization of technology takes us on another level where you have learning thermostats that can learn from our setting of temperature, and while accessing the outside temperature, our preferred temperature, as well as inside temperature they provide us a likely temperature that we like most. It all happens because of Wifi capabilities and AI intelligence. Wifi capability gives us remote control access so we can control the thermostat from a mobile device or a tablet and pc. No C Wire Smart Thermostats That Work Without Common Wire is the best example of modern technology.

But the story never ends here modern thermostats can integrate with AI-based home assistants that made to take and communicate voice commands and become a bridge to control the whole smart devices from a single place. I like to explore and always pay attention to the technical side and figure out that, modern thermostats are equipped with dozens of sensors and need to stay updated and communicate a lot; all of these require the power to run effectively, most common and know source to get power in thermostats is a C-Wire whom we call common wire. Previously there were many solutions available which run on batteries but in the previous decade concept of C-wire evolve and the majority of new thermostat depends on this low voltage wire for power. Until the Birth of smart and learning thermostats, it was nearly impossible to run a thermostat without C-wire or batteries. Every manufacturer was making the thermostats that run on C-wire or using batteries. But wait!

Believe me, it is hard to run a smart thermostat smoothly without C-Wire, without C-Wire either it will drop charging or stop working, getting stuck or you will have fan issues. In every case the issue is different, to keep the smart thermostats up and working you need to power them with a C-wire. There are few modern systems where you may not need a C-Wire but in actual its required, or choose an old age thermostat that runs on cells/batteries. 

Modern thermostats equipped with a backup battery, and they are energy-efficient, and they need only a fraction of power to run as compared to old thermostats. These energy-efficient devices can charge their battery and take power from the heat and cool wires so that they can run without C-Wire. Recently I publish a Honeywell wifi thermostat review please consider this budget-friendly thermostat.

How to Check if Your Thermostat has a C Wire?

It’s simple; detach your old thermostat and check if the thermostat has a c wire. If you there is terminal with the name of C is attached to it, that means you have a c wire installed system. In many cases, it is hidden, especially when it was not required to run your old replaceable battery-powered thermostat; to find it, you need to check your furnace. There is a high chance that a C wire is hiding behind the wall. 

Before buying a new thermostat, it is necessary to check the c wire availability and compatibility of your new selection with your installed HVAC system so you can expect smooth operations and easy installation without incurring any additional cost.

In this article, I list some of the best available thermostats that work without c wire, and all of these solutions modern and can connect to WiFi and AI-based home assistants.

Is Power Adapter An Alternative to C-Wire?

C wire adapter 24 Volt Transformer for Ring Doorbell Nest Honeywell Emerson Sensi Smart Wifi Thermostat Ecobee Nest Hello Skybell Thermostat UL Certificated (26ft/8m)
HAUTURE C wire adapter 24 Volt Transformer

Yes, it is an alternative to C-wire and a lifeline for thermostats, which has the necessary C-Wire requirement, but your system does not support that. A power adapter plugs into the standard power source and can convert that to a low voltage equivalent to C-Wire. It usually costs you a few additional dollars but an authentic solution and alternative of C-Wire.

Many manufacturers include power kits in their standard package, so if your old system is not using c wire or not installed, you can power up your thermostat while using that power kit. 

2 Smart Thermostat No C Wire

The solution to C-Wire is very simple and straightforward and instead of looking for a thermostat that works without C-Wire prefer to buy a transformer that will be an alternative to C wire and provide the required power. These transformers are very compact and available easily as one is listed above. While some producers include these in the package so in case you do not have C-Wire in your existing setup you can use an adapter to power up your thermostat.

Google Nest 3rd Gen Learning Thermostat

smart thermostat without c wire

Google Nest 3rd Gen Learning Thermostat has improved the original formula and first on the scene as a third-generation thermostat. It is equipped with some excellent and powerful features, gorgeous display with the multi-color option, and having an overall futuristic look. I believe that this is the only thermostat in the market which works without C-Wire and can work without C-Wire with most of the new heat and cools the system. Usually, it does not need a C-Wire when it gets power through heat and cool wires, but this is not the case with all of the heat and cool systems, and there is no clear compatibility list available, so if a power cycling issue arises then arrange a common wire through a power adapter.

Its AI-based learning feature makes it different from others that learn from the user setting, and while considering outdoor and the indoor temperature, it brings the best temperature to the user that he like and most and allows to set different profiles for individual users. On the other hand, rooms sensor support makes it a single solution for a complete home.

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Ecobee SmartThermostat with Voice Control

smart thermostat no c wire

Ecobee Smart Thermostat with Voice Control comes with a power extender kit. So, no need to worry if it will not work without C-Wire, you can use the power extender kit that is included in the package. You will not bear any extra cost; it’s a complete solution with 32 room sensor support and Alexa built-in. Now you can talk with your thermostat, and it will become a central point to control all of your smart devices. It can integrate with other smart devices in the home. It is equipped with modern processors that are fast and make it responsive as well as efficient. 

It’s packed with a lot of features that are only possible with thermostat, can make schedules, and also compliant with energy-saving schemes. Overall it can save you 23% on heating and cooling bills in a year and will add value to your house because it’s elegant and packed with the features that smart homeowners want nowadays.

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I recommend you to choose an option that you like most and fully compatible with your HVAC, if C-wire is not installed then you can buy a power extender kit or a transformer that will cost you between 10 to 15 dollars. Such power adapters come with long wires that make it possible to plug in at any convenient plug or on the other side of wall where it’s not visible. I experienced both the power extender kit and the power adapter. I found that; to attach a power extender kit, you need an additional wire in existing wiring or need to free one, which is not useful, to power up your thermostat. This practice also requires technical knowledge and will take a lot of time while the power adapter is easy to use and easy to attach, in actual its an easy to use and does not require any in-depth knowledge of installation.

Why does a Smart Thermostat require a C-Wire?

The reason is straightforward, a smart thermostat needs a constant flow of electricity from the furnace to keep the thermostat running. Smart thermostats equipped with:

  • Wifi
  • Sensors, a dozen of 
  • Display
  • Bluetooth connectivity
  • They also need the power to integrate with smart devices

All of these require a continuous supply of power to stay connected and to keep you updated, and unfortunately, if these smart thermostats run on batteries only, then that will last only for an hour or two. Batteries will not provide them enough power to stay responsive and cannot keep them alive for enough periods; thus, the C-Wire is an only long term solution to provide reasonable and uninterrupted power.

Some of the modern models, as listed above, are equipped with circuitry that captures the intermittent power from the red wire that charges the internal battery of thermostat. It means that can completely without C-Wire, but such there are only a few furnaces where red wire carries reasonable voltage that can charge the thermostat battery. Even sometimes, when it works, it starts losing power and run on battery only and encounters other problems. But surely if you have a modern furnace installed, then it can work smoothly.

My Picks of 8 Best Smart Thermostats

ProductDescription
1 Ecobee SmartThermostat with Voice Control
5GHz WiFi support and Quad-Core processor
Built-in Alexa
Made to save 23% on energy bills 

Shop now at Amazon
2 Google Nest 3rd Gen Smart Thermostat
Futuristic design
An excellent learner
Farsight lights it up to show necessary information
Room sensor support

Shop now at Amazon
3 Ecobee4 Smart Thermostat with Built-In Alexa
Power extender kit
Work without C-Wire 
Room sensor support
It can sense your presence

Shop now at Amazon
4 Honeywell Home T9 WIFI Smart Thermostat
Sensors have a remarkable range of 200 feet
Access through the app
Alexa and Google Home compatible

Shop now at Amazon
5 Google Nest Thermostat E
Frosted display
Provides remote access to thermostats
Energy saving
Compatible with Alexa
Simple schedules

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6 Ecobee3 lite 2nd Gen Smart Thermostat
Has all modern-day features
It works with all of the favorites
Compatible with most heating and cooling systems used in the USA

Shop now at Amazon
7 Emerson Sensi Touch Wi-Fi Smart Thermostat ST75
Energy Star certified
Extensive compaitbility
Full access to energy report
Work With Favorites
Work without C-Wire 

Shop now at Amazon
8 Honeywell Home T5 Plus Smart Thermostat
Seven-day flexible scheduling
Smart alerts
Automatically change from heat to cool
Alexa connectivity
C-Wire is a mandatory 

Shop now at Amazon

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