<!-- from fixya rte -->How do I wire a Honeywell thermostat - Heating & Cooling

Can I start by saying I am not in anyway saying to do this alone it is dangerous but if u must follow each step start by being safe shut off the breakers good luck here to help
Step 1
Turn the air conditioning and heating unit off by flipping the appropriate circuit breaker. Test the unit to make sure it's off by turning your existing thermostat to the "On" position and seeing if it turns on. Wiring a Honeywell thermostat when the circuit breaker is on could cause you to blow the transformer that powers the HVAC unit Step 2

Connect the red wires to the thermostat RH, thermostat RC or thermostat R terminal. The thermostat RC terminal has a jumper wire between thermostat RH and thermostat RC. The thermostat R terminal operates both the heating and cooling units, and contains an internal jumper wire. Basically, your red wire on a Honeywell thermostat is the hot wire that run. Step 3

Run the green wire to the thermostat G terminal. The green wire controls the relay that operates the blower, and it controls the fan. Step 4

Control your air conditioning when you connect the yellow wire. It connects to the thermostat Y terminal Step 5

Hook the white wire to the thermostat W terminal to control the heating unit