Your programmable Honeywell thermostat can help you save up to 33% on your utility bill. It adjusts the temperature up and down according to your schedule, so you use energy when you need it and conserve energy when you're away. When you install your Honeywell thermostat, it's important to understand its wiring. Learning to wire a Honeywell thermostat is easy when you determine the colour-coded system.
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.
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 runs from the transformer.
Run the green wire to the thermostat G terminal. The green wire controls the relay that operates the blower, and it controls the fan.
Control your air conditioning when you connect the yellow wire. It connects to the thermostat Y terminal.
Hook the white wire to the thermostat W terminal to control the heating unit.
When replacing your thermostat, it's normal to have extra wires in your existing thermostat that you don't need for your Honeywell thermostat. When the house was built, your contractor may have used a five or eight-wire thermostat, but that's not necessary needed today.