The 4 best smart thermostats that don’t require a C-wire

Upgrading your thermostat to a smart thermostat is a great way to save money on your monthly utility bills, but it’s not a decision to make lightly. Beyond sifting through dozens of products and finding ones that offer all the features you’re interested in, you’ll also need to make sure it’ll work with your existing HVAC system. And if you live in an older home or one without a C-wire, shopping for a smart thermostat can be challenging.

Thankfully, there are a handful of great smart thermostats that don’t require a C-wire. Here’s a closer look at four smart thermostats you should consider.

The Nest Thermostat E installed on a wall.

Google Nest Thermostat E


  • Easy installation
  • Powerful smartphone app
  • Minimalist design

The Google Nest Thermostat E offers just about everything you’d want from a smart thermostat. It’s sleek, it’s easy to use, and installation is about as simple as it gets. Best of all, a C-wire isn’t required – although it might not be compatible with all setups, so be sure to use Google’s guide before making a purchase.

If everything checks out, you’ll be treated to one of the best smart thermostats on the market. Featuring a frosted screen, the understated thermostat easily blends in with most home décor and looks much more modern than traditional units. It also comes with a unique feature that lets you know you’re running at an eco-friendly temperature by showing a Nest Leaf on the display.

Other notable features include the ability to set schedules, sync with Google Home, and scroll through your Energy History charts to see how you can improve your usage.

Google Nest Thermostat E - Programmable Smart Thermostat for Home T4000ES - 3rd Generation Nest Thermostat (Frosted White)- Compatible with Alexa
Ecobee3 Lite installed in a home.

Ecobee3 Lite Smart Thermostat


  • Modern design
  • Syncs with other Ecobee products
  • Support for Alexa, HomeKit, and Google Home

This entry comes with a bit of a caveat – while the Ecobee3 Lite doesn’t require a C-wire, you’ll probably need to install a power adapter (which is included with your purchase). It’s not an impossible task for the average homeowner, although it does involve some rewiring. But if you don’t mind spending a few minutes tinkering with your setup, the Ecobee3 Lite is a great option.

Ecobee says you can save up to 23% annually on your heating and cooling costs, making this a smart investment. It also integrates nicely with other Ecobee products, as you can install a variety of sensors to allow your thermostat to turn off when a window is opened or when you leave for the day. Coupled with an intuitive smartphone app and a sleek thermostat design, its easy to see why the Ecobee3 Lite is so popular.

ecobee3 lite Thermostat

Ecobee3 Lite Smart Thermostat

Sensibo Sky on a white background.

Sensibo Sky


  • Designed for standalone air conditioning units
  • Easy installation
  • Versatile smartphone app


  • Doesn’t support central air conditioning units

Folks without central air conditioning aren’t left out of the smart thermostat fun, as the Sensibo Sky is designed specifically for portable, wall-mounted, or standalone units. It works with most models on the market that are remote controlled, allowing you to quickly turn them into a smart appliance.

The Sensibo Sky is smart enough to turn your AC on and off when you’re arriving or leaving, adjust the “real feel” of your home on the fly by measuring both humidity and temperature, and it even lets you program in a schedule for its performance. It might not be as robust as other smart thermostats, but if you’re working with a standalone unit, it’s hard to find a better device than this.

Sensibo Sky, Smart Home Air Conditioner System - Quick & Easy Installation. Maintains Comfort with Energy Efficient App - Automatic On/Off. WiFi, Google, Alexa and Siri. (Grey)
The Lux Geo smart thermostat installed in a home.

Lux Products

Lux GEO-WH Thermostat


  • Multiple power options
  • Simple installation
  • On-unit and smartphone controls

It may not be the sleekest smart thermostat on the block, but it’s arguably the easiest to install. The Lux GEO-WH can be powered by a C-wire if your home is equipped with one, but you can also run it with a micro-USB cable or AA batteries. Beyond its old-school design, the Lux GEO-WH offers everything that makes smart thermostats great. This includes a programmable schedule, remote access through a smartphone app, and enough flexibility to help you lower your energy bills. It’s also relatively affordable, making it a great option for older homes that may not be equipped with a C-wire.

Lux Products GEO-WH Wi-Fi Thermostat, White

Editors’ Recommendations

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