A thermostat is a device used to regulate the temperature in our homes and cars. If your current thermostat isn’t working very well, it might mean that it’s time to replace it.
If so, you might want to change the old thermostat to a new, smart model. This task, on the surface, might seem a little intimidating; there is a lot of wiring to deal with, after all.
But in fact, learning how to replace a thermostat in your home is easier than it seems, and it will take much less time than you might anticipate.
Replacing Your Thermostat – a Guide
When you decide to replace your thermostat, the most important thing to remember is to take it slow and not rush the process.
In some cases, it might be a useful idea to take pictures of each step, especially the wiring, so you can always refer back to the images if you get confused.
Buy a Compatible Thermostat
This would be the first step. If you don’t have the correct type of thermostat, you’ll need to make another trip to the store once you realize it’s not working.
Around 90% of replacement thermostats will work with any type of system you have at home, but there are those which are unique. That’s why reading the labels on the new thermostat is crucial.
The manufacturers will name the system their devices are compatible with. For example, it might say something like “Works with Direct Line Voltage” or “Works with Zoned HVAC.”
Read the Instructions
No one likes reading the instructions on the package. There are usually too many details, and the print is too small. Besides, you can figure this out on your own, right?
Of course, but it’s better to be safe than sorry, and the instructions might hold a vital detail that you don’t want to miss.
Turn Off the Power Source
Whenever you’re working on a DIY project that involves electricity, remember to turn off the power source.
Look for the electrical panel in your home and turn off the switch for the thermostat. It’s usually labeled. But if it’s not, try a few switches and see which one shuts off the thermostat.
Remove the Old Thermostat
Home thermostats are usually attached to a wall. You’ll need a smaller screwdriver to remove the screws from the sides of the wall plate.
Some thermostat models have a sub-base too.
If you remove the plate and there’s another layer, you need to remove it as well. All that you should see are the electrical wiring coming out of the wall.
Observe and Disconnect the Wiring
This is probably the most relevant step you need to pay attention to. Take a photo of how the old thermostat is connected. Or grab a pen and paper and write it down or draw a diagram if you prefer.
You can use some tape to label each wire, so you can recognize them easier later. Unlike some other home appliances, the wiring isn’t always color-coded in thermostats, so don’t rely on that detail too much.
Finally, proceed carefully and disconnect the wires and remove the thermostat altogether. The wires hanging from the wall should be either taped together or connected to an object that will weigh them down a bit.
The issue here might be that a wire or two will recede back into the wall, and you won’t be able to get them out. This would mean you have a much more complex issue on your hands.
Install the New Plate
Now it’s time to start installing the new thermostat, beginning with putting in the new plate. You can use it to mark where you need to drill new holes for the screws first.
And once you drill it, install the new plate itself.
Keep in mind two things here — first, to use a drill that’s the size of the screws. And second, to buy anchors if they didn’t come in the package because you’ll need them for support.
Connect the Wiring
How to replace a thermostat correctly will mostly depend on disconnecting and then reconnecting the wiring system. If you’ve diligently organized and noted the disconnecting process, you’ll have no re-wiring issues.
This is where the instruction manual on the package of your new thermostat might be quite useful too. But there are no clear rules when it comes to home thermostats.
Some will have just two or three wires, and others will have more than five.
Attach the Thermostat to the Wall
Collect all the wiring that’s sticking out from the wall or that are left exposed and push them back into the wall.
Now take your thermostat and adjust it properly to the wall, a little above the wall plate, preferably. Use the screws to attach it to the wall plate itself.
Turn the Power Back On
Go back to the electric panel and turn on the switch for the thermostat. Don’t worry if it doesn’t work immediately.
Often, it takes a few minutes before it gets going. Also, since most thermostats need batteries, make sure you have AA batteries on hand and that you insert them correctly.
Check the Thermostat
To be absolutely sure you’ve done a good job, you might need to test the replacement thermostat. Set it to the desired temperature and give it around 10 minutes.
If the temperature in your home doesn’t change, then the wiring must be off, so you’ll have to try again. That said, some thermostats have a reset button that you need to press before they start working.
Final Thoughts
Even though it can sometimes turn into a messy project, knowing how to replace a thermostat is a handy skill to have.
You might run into problems like the new thermostat being much smaller than the old one. Therefore, you have to repair the wall as well.
Or the new smart thermostat doesn’t have the low voltage it requires. But in most cases, there won’t be any issues provided you choose a compatible replacement.
Just remember not to rush it, and you’ll be done in less than an hour. Then you’ll be able to enjoy the new thermostat and have the satisfaction of installing it yourself.