install a thermostat

How to Install a Thermostat

Replacing your old thermostat with a newer model can help you lower your utility bills, make your family members more comfortable, and even increase the value of your home. You can install your new thermostat by yourself in one or two hours, and it will quickly pay for itself through energy savings. Here are the steps you should take to install a thermostat in your Illinois home.

Choose Your Thermostat

install thermostat

Image via Flickr by brendan-c 

A programmable thermostat can turn down your HVAC system at the same time each day when you leave for work or go to bed and then reactivate it before you come home or wake up. You can control a smart or Wi-Fi thermostat through your computer or smartphone as well. That way, you can make alterations from anywhere if your schedule changes, and you can get detailed reports about your heating and air conditioning system’s energy efficiency.

Many smart thermostats can also learn your routine over time, letting you avoid spending time programming your preferences and schedule. Smart thermostats can look sleek and high-tech, and with many, you can choose the color of the display or even set a background image. Make sure that the thermostat you choose is compatible with the type of HVAC system in your home, its voltage, and the location where you want to install it.

Assemble the Tools Required

To install a new thermostat, you’ll need a few different sizes of Phillips screwdrivers,  cordless drill with drill bits, a level, painter’s tape or masking tape, a permanent marker, and a pencil. If you plan to use the holes that are already in your wall from your current thermostat, you may not need a drill.

Turn Off Power to Your HVAC System

Before you start installing a new thermostat, you’ll need to cut power to your existing thermostat. Otherwise, you could receive an electrical shock while working with it. Find the main electrical service panel in your home and then turn off the correct circuit breaker. It should be labeled as HVAC or with the area of your home that houses your heater and air conditioner. For example, you might need to turn off the circuit breaker labeled basement if that’s where your HVAC unit is. If your circuit breaker isn’t labeled clearly, you should contact a professional

Remove the Old Thermostat

First, take the cover off your current thermostat. You can pry open most covers easily with a knife, but some should be unscrewed instead. After you remove the cover, you should see one or two screws holding your old thermostat to the wall. Remove these, and pull on your thermostat gently to move it one or two inches away from the wall and expose the wiring attached. Most thermostats have two to five wires.

Use the masking tape and the permanent marker to label which wires connect where. Then, disconnect the wires and discard the old thermostat. To keep the wires from falling into a wall cavity, wrap them around a pencil or tape them to your wall.

If your previous thermostat contains mercury, you should see a small glass tube with a shiny, sliver substance inside it. To prevent pollution, you should only throw it away at a hazardous waste disposal site. Until you can get rid of your old thermostat, store it in a sealed container where kids and pets can’t reach it.

Check for a Power Source and Add Wiring if Needed

If your existing thermostat only has two wires, it’s probably battery-powered and not connected to a power source. However, your HVAC system could already have the wiring you need for a smart thermostat that needs more power and has more features.

People often call the wire that provides power to a thermostat the common wire or C-wire. An unused C-wire could be inside the wall behind your old thermostat. Use a flashlight to look for it. If you don’t find it, you should check the HVAC control board on your HVAC system to see if a wire is connected to the C terminal. The HVAC control board is usually on the surface of your indoor heating and air conditioning unit or inside an access panel. If it has a C-wire, you may be able to trace its path and locate it inside the wall.

If there’s no C-wire, you can add one with a special kit. Some smart thermostats come with this kit. If you HVAC system doesn’t have a connection for a C-wire, you can buy an adapter that you can use with a regular power outlet. If you need help, contact an experienced HVAC technician.

Replace the Back Plate

Most thermostats have a back plate to help ensure they hang securely on walls. Unscrew the back plate for your old thermostat, and replace it with a new one. Use the level to make sure the back plate is in the right position, and then mark the locations where new screws should go. If you don’t already have holes in those places from the previous thermostat, use the drill to make new holes.

Mount Your New Thermostat and Restore Power

Use the labels you made earlier to attach the wires from your HVAC system to your new thermostat. You can consult the connection diagram in your new thermostat’s owners’ manual if needed. Make sure the wires are in good condition, and install a battery for your thermostat if necessary. Screw or snap on your new thermostat’s cover, and then switch the circuit breaker for your HVAC system back on. To maximize your savings, program your new thermostat to suit your schedule and temperature preferences. Also, test it to make sure that all the controls work.  

For help installing a new thermostat or maintaining your HVAC system, contact us at Dahme Mechanical Industries. We can help you choose and install a programmable or smart thermostat with all the features you need. We’ve been in business since 1965, and we’re devoted to providing quality service for our customers.