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How to Install a New Thermostat

A new thermostat could reduce your energy bills. Replacing your old manual thermostat with a digital programmable one will relieve you of having to remember to change your temperature settings every time you leave home. For most HVAC systems, learning how to install a new thermostat is relatively simple. You can do yourself if you have a basic knowledge of electricity and how to use simple hand tools.

Following is a brief summary of how to install a new thermostat. If you are uncomfortable with doing this job, or if you get stuck at any step along the way, call an expert to do it for you.

  • Buy a thermostat that is compatible with your HVAC systems.
  • Review the directions that are included with the new thermostat.
  • Turn off the power to your HVAC system. Put a sticky note or tape on the circuit breaker switch to keep anyone from turning the circuit back on while you are working on it.
  • Remove the old thermostat from its wall plate.
  • Draw a diagram with color-coding to show how the existing thermostat is wired.
  • Disconnect the wires and wrap them around a length of wooden dowel to keep them from falling back inside the wall.
  • Remove the old wall plate. Place the new wall plate in position and mark screw holes. Drill holes into the wall and insert drywall anchors as needed.
  • Pull wires through the hole in the new wall plate, then screw the wall plate into the wall.
  • Cover the exposed hole with tape or insulation to keep cold air in the wall from interfering with the new thermostat’s operation.
  • Attach wires to the terminals on the new thermostat according to the directions or to match your original wiring diagram.
  • Slide or snap the new thermostat onto its wall plate.
  • Turn power back on and test the new thermostat for correct operation in both cooling and heating modes.

If you want one our HVAC technicians to explain how to install a new thermostat or to do the installation for you, contact us at HVAC & Plumbing Unlimited. We help homeowners throughout northern Virginia keep their homes comfortable and energy efficient in every season.

HVAC Unlimited Inc.
Jeremy was a very nice and knowledgeable guy. He explained everything so I could understand it, which was great. Highly recommend.
Dana - Manassas, VA
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