Most home thermostats are hard wired into the furnace. They have a low voltage control wire that runs from the thermostat to the furnace, which is how the thermostat communicates with the furnace. Wireless thermostats allow more flexibility with the placement of the thermostat. If you want to relocate the thermostat at a later date, you don't have to run a new wire in the wall if you have a wireless thermostat. You can keep the thermostat near you to further increase your comfort. It is fairly easy to install a wireless thermostat, and is actually less complicated than a hard-wired one.
Turn off the power to the furnace by turning off the breaker in the circuit breaker panel.
Remove the existing wall thermostat by gently pulling it off until it unsnaps from the wall plate. You may need to remove a few screws before it will pull off the wall plate.
Disconnect all the thermostat wires from the thermostat and label them according to which terminal they connected to. Remove the wall plate from the wall.
Mount the wireless thermostat receiver wall plate to the wall with drywall anchors and screws.
Connect the thermostat wires to the terminals on the wireless thermostat receiver. Connect them up to the appropriate terminals.
Mount the receiver to the wall plate by pushing it on until it snaps into place, or tighten screws as required.
Turn the power back on to the furnace.
Put batteries in your wireless thermostat and turn it to your desired setting. When the thermostat calls for heating or cooling, your furnace should run.
Keep an eye on the batteries and replace them as necessary to keep your thermostat operating properly. Keep the thermostat within proper operating range of the wireless receiver. If it's too far away, the thermostat may not communicate with the receiver and the furnace will not operate.
Keep the power turned off to the furnace when working on the thermostat wiring. Damage to the furnace and/or electrical shock may occur if the power is left on.