The white wire underneath your thermostat connects to your heating system. It terminates at your air handler or furnace. The white wire connects to terminal W in industry-standard thermostats.

What are the wires on a 2 wire thermostat?

2 Wire Thermostat Wiring (Furnaces) The most basic thermostat has 2 wires; usually a red and a white wire. Two wire thermostat wiring is used for furnaces only and usually doesnt need a “C” or “Common” wire. Thats why we only need two wires: Red wire for power (24h).

Will a Nest thermostat work with two wires?

Both the Nest E and Nest Gen 3 Thermostats can be installed with 2 wires. If you have a heat only system you should connect your thermostat wires to the W terminal and Rh terminals. If you have a cooling only system you should connect your thermostat wires to the Rc and Y terminals.

How should my Nest Thermostat be wired?

If your thermostat doesnt have a separate connector labeled C and youre not sure what type of system you have:A brown wire is mostly likely a heat pump wire and should be connected to the O/B connector on the Nest thermostat.If the B wire is blue, it should most likely be connected to the C connector.