How to Wire a Room Thermostat

A room thermostat is a great way to control the heating and cooling in your home. It can be a time saver and help you reduce your energy bills. But there are some things you should know before you start wiring your new thermostat.
First, you need to make sure that your old thermostat is disconnected from the wall and that there are no wires hanging loose or unconnected. If you aren’t confident in your skills, you may want to consider hiring a professional for this job.
To prepare for the installation, take a picture of your existing thermostat’s wiring scheme so you can use it as a reference. This will also ensure that your new thermostat is connected to your HVAC system correctly.
Once you’ve got a photo, remove and label each wire (and any terminal that’s not on the photo). It’s important to note that the color code is not always the same for each individual wire.
Red Wire: Power – 24 Vac input in most cases, connects to the RC, RH, or 4 terminals internally.
White Wire: Line – connects to the W or W1 terminal on your thermostat.
Green Wire: Ground – connects to the G terminal on your thermostat.
Blue or Yellow Wire: Fan – connects to the F terminal on your thermostat.
C Wire: Common – connects to the C terminal on your thermostat.
Once you’ve determined that you have a five wire thermostat, the next step is to replace your current thermostat with the new one. This is a pretty simple process that involves removing the old thermostat and then reconnecting and attaching the wires to the new thermostat.
In some cases, you may need to bend the wires so they don’t fall back into the wall when you pull them through the hole in your wall. Once you’ve done this, secure them to the wall with painter’s tape, so they don’t fall in while you prepare the new thermostat for mounting.
Using the new thermostat’s backplate, mark where the screws will go. Drill guide holes and add sheetrock anchors if necessary. Once you’ve done this, screw the backplate into place and verify that it fits tightly.
When you’re ready to put the thermostat back in place, reconnect the wires and check them twice to make sure they match up correctly. If you have any questions, consult the thermostat’s manual.
If you don’t have a manual, it’s best to get one before you begin the installation. This will provide you with a step by step guide that will help you avoid making any mistakes that could damage your thermostat or the HVAC system in your home.
If you’re comfortable working with wires and are not afraid of a little bit of sweat, you can install a thermostat yourself. The process is easy and should only take a few hours of your time. However, if you have more complex systems like heat pumps or multiple zones, it’s a good idea to hire a professional to handle this part of the installation.