Introduction: Installing a New Thermostat

This is a step by step instructional video on installing a new thermostat for your heating and cooling system. Please be aware to check the new thermostat's capability with your existing HVAC system. In general most systems will be compatible with a 1 Heat/1 Cool thermostat, however if you have a 2 stage system installed in your house you will need a 2 Heat/2 Cool thermostat.


Digital multimeter, Slotted Screwdriver, Phillips Screwdriver, Wire Stripper, Pocket Screwdriver, Level

Step 1: WARNING!!

CAUTION! Before beginning make sure to turn power switch off at the furnace. Personal injury or equipment malfunction is possible if power is not turned off while changing thermostat.

Step 2: Ensure Power Is Off at Thermostat

Set the multimeter to read AC current and put the probes on the connection for the red wire (Marked "R") and the white wire (Marked "W"). If the power is off to the system you will read no voltage (0) on your meter. If you are reading voltage of 24 - 35 volts turn the breaker off to the furnace and recheck your voltage.

CAUTION! Do NOT proceed with installation if there is voltage on the wires. Voltage can cause personal injury and also malfunction of your HVAC system.

Step 3: Identify Wire Colors

Identify which wire colors are attached to which terminals on the existing thermostat and be sure to write down the color and the terminal. In many cases the red wire will be on the "R" terminal, the white wire on the "W" terminal, the green wire on the "G" terminal. However, all houses are different and if new wiring has been run or the old wiring did not have those colors it is important to notate the colors for later use.

Step 4: Remove Screws and Pull Thermostat Away From Wall

Remove the screws that hold the thermostat to the wall and carefully pull the thermostat away from the wall. You may have to pull on the wire in order to get the thermostat to come away from the wall. Leave the wires connected to the thermostat to ensure the wire does not pull back into the wall.

CAUTION!! DO NOT PULL EXCESSIVELY ON THERMOSTAT OR WIRES. If the thermostat and wire do not pull from the wall with minimal pulling do NOT continue to pull. There is a possibility that it is a short wire and tugging will run the risk of breaking the wire.

Step 5: Remove Wires and Re-Strip

If possible you would like to expose new, fresh wire for the installation of the thermostat. Once you have removed the old thermostat if you have enough wire it is best to re-strip the wire. Using wire strippers remove about 1/4" of the insulation off the wire to expose new wire. See the attached video on properly stripping wire.

CAUTION!!! When stripping wire DO NOT cut through the entire wire.

Step 6: Remove Front Cover of New Thermostat

Carefully remove the front cover from the new thermostat in order to get to the mounting plate which is located behind the front cover. Refer to thermostat install instructions for detailed instructions on how to remove front cover. Most covers simply pull off but do NOT force cover.

Step 7: Mount New Thermostat to Wall

Feed the wire through the opening in the back of the thermostat and mark where the new screws will be located on the wall.

Step 8: Level Thermostat and Install Screws

Screw the new thermostat to the wall using the included anchors and screws. Make sure to use a level to level the thermostat. Although new thermostats do not have to be perfectly level in order to operate correctly it is best to make sure it is level for good aesthetics.

Step 9: Locate New Terminals for Wire Installation

Terminals will be marked on the new thermostat. Locate the letters that were utilized on the original step and which wire colors were attached to them. Refer back to the notes that you took in Step 2. You must make sure that you install the correct wire color to the correct wire terminal.

Step 10: Install Wires Onto New Thermostat Terminals

Loosen the screws on the terminals you will be utilizing. Slide the exposed wire onto the terminal and tighten the screw down. Give a slight tug on the wire after tightening the screw to make sure of a good connection.

CAUTION!! Do NOT overtighten the terminal. You are simply making a connection with the wire. Over torquing the screw could cause the thermostat to crack.

Step 11: Check Gas/Oil - Electric Heat Switch

Most thermostats come with a switch setting for gas/oil or electric heat. If your house is using natural gas or propane switch should be set to Gas/Oil. If your house is utilizing a heat pump with back up electric heat then you choose electric on this switch.

Step 12: Install Batteries

Install the batteries into the thermostat being sure to follow the battery diagram on the thermostat and also be sure to use new fresh batteries.

Step 13: Put Cover Back on Thermostat

At this point you can put the thermostat face back on the thermostat and carefully snap back into place. Thermostat should be illuminated and working. Set the temperature setting for the house.

Step 14: Turn Power Back On

Switch the furnace switch back to on. If you had to turn off a breaker in order to turn off the power, switch the breaker to on and switch the furnace switch to on. Turn the heat up and make sure that the furnace turns on.