Best smart thermostats that don’t require a C wire 2021

Our top pick for the best smart thermostat without a C wire goes to the Nest Thermostat E. It’s an excellent option for folks who don’t want to spend too much and prefer minimalist devices. The display shows the temperature setting, while the app lets you prioritize certain rooms’ cooling, change settings when you’re away, and lets you know if it senses a problem. Most importantly, the Thermostat E features a built-in rechargeable lithium-ion battery that bypasses the C Wire requirement.

Eco Bees 5th-gen smart thermostat builds upon everything that made its predecessors great (up to 32 room sensors, great display, plays friendly with all the intelligent assistants) by adding built-in Alexa voice control and a speaker. Like its eco bee brethren, the fifth-generation model doesn’t need a C wire, but it does come with a power extension kit that you’ll need to wire to your furnace control board.

The rare smart thermostat that’s compatible with 120V–240V, electric baseboard, and fan-forced heaters, the Mysa Smart Thermostat can mostly be installed yourself in a few minutes, is consistent with Alexa, Google, and HomeKit, and has all the intelligent tools you need to cut down on your energy usage. App scheduling, geofencing to track when you’re away from home, pre-heating or pre-cooling based on your schedule, and in-depth energy reports for possible improvements.

Nest’s Learning Thermostat remains one of the smartest and most good thermostats today, supporting multiple zones, learned schedules, Alexa/Google Assistant integration, and HVAC monitoring. It also doesn’t need a C wire, though some users have discovered power cycling issues that may or not be an issue for you without a C wire. It’s good enough that we’ll recommend risking a purchase regardless.

The newest Nest is another thermostat that can work without a C wire, but in our Nest Thermostat review, we had to wire one in. It depends on whether your R and Y wires reach the voltage necessary to power everything; otherwise, your Nest Thermostat will shut down certain features to ensure the core temperature control still works. If your HVAC is fully compatible, it’s a versatile and affordable machine that uses geofencing and motion tracking to detect when you’re not home, saving you plenty of money.

The ecobee three lite misses a few conveniences features that the 5th-gen has, like a built-in occupancy sensor and voice control. However, it’s an excellent budget option, and you can still fully control your home’s heating and cooling from anywhere in the world through the app or in your home with intelligent assistant devices. The ecobee3 lite also comes with a power extension kit to circumvent the need for a C wire.

The fourth-generation model is an excellent mid-tier option to save a little money compared to the newest Ecobee thermostat. Like the Ecobee smart thermostat, it has built-in Alexa, works with Google Assistant and HomeKit, is compatible with remote room sensors, and has identical energy savings. You’ll miss out on Alexa calling, Spotify connects, Bluetooth streaming, the 5.0 wifi band, and the newer model’s excellent glass display.

If you don’t mind a bit of a dated look and lack of a 24/7 light-up display, Emerson’s Sensi smart thermostat is your best budget pick. It only requires a C wire for heat- and cool-only systems (or heat pumps), and it still has full wifi connectivity, a straightforward app, easy program controls, and minimal setup required.

C wire aside, some of you may not have central air but will still want to manage the climate throughout your home. For that, the Sensibo Sky controls your window or mobile AC appliances, letting you set up conditioning or heating schedules or pick specific temperatures through wifi monitoring. Plus, it makes your AC units controllable through Echo or Google Home commands.