Smart Thermostat that doesn't require a C wire?

Are there any smart thermostats that don’t require a C wire? My house was built in '79 and does not have a C wire running to either the 1st or 2nd floor thermostats. There aren’t any wall outlets nearby/accessible either

Thanks in advance.

The C Common wire is what will supply power from the furnace to the thermostat. Without it, you will require a thermostat that runs on batteries. I believe the original Nest could support this configuration, but my friend, who suffered it, did not enjoy it and ended up replacing the Nest back to the original thermostat that was originally in place. Granted, it’s quite cold here in Canada in winter, so you absolutely do not want to risk a thermostat failure unless you want burst (frozen) pipes and a huge mess.

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My other option, I suppose, is a programmable thermostat … but that just seems so… 90’s :grin: :grin:

I’ve heard good things about the EcoBee because it supports in room remote occupancy and temperature sensors. I do not know if it supports a mode that doesn’t require a C wire.

A recent episode of one of the shows discussed the EcoBee. I’m trying to remember which/what. I’ll reply again here if it comes to mind.


What is the heating source? Furnace? Electric baseboard? Radiant floor?

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I have the ecobee 3 lite, it does come with a separate power supply that allows installation w/o a C wire. Don’t know about the other models though.

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So it was Andy Loves the Listeners at about 1h49m20s. @mikahsargent was discussing an EcoBee add-on.

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It’s a gas boiler with forced hot water baseboards

@ rmquist,
Eccobee does not require a C-wire. They include a kit that taps other wires to provide the power for the thermostat. They’ve had this tech since their earliest models.

Nest thermostats can work wirelessly, you put them on the stand and power them from usb so aren’t tied to fitting them in the same location as your current thermostats.

Saguaro beat me to it. The ecobee power extender taps into the wiring at your furnace ac source and provides power to the thermostat