DIY – How to install a Digital Thermostat

You know what we hate at Koopman Lumber? Wasting hard earned money. That’s why we’re looking today at a quick way to save some significant cash year-round with digital thermostats. They are one of the hottest products on the market for improving home energy efficiency. “But Koopman Lumber, I’ve never dealt with electrical work!” you say. Never fear! We’ve written this blog with you in mind and can guarantee this is as simple as can be.

Difficulty: Easy
Time: 30 Minutes

Supply List:

  • New digital thermostat
  • Screwdriver
  • Drill
  • Screw Anchors
  • Masking tape
  • Pencil
  • Torpedo Level
  • Safety Glasses


If you have an older home, chances are you’re very familiar with the image on the right. These old analog thermostats have been a mainstay in heating people’s homes for years, but in today’s efficiency-conscious market, they don’t quite make the cut. Between inflated heating bills from inaccurate readouts and forgetting to turn your thermostat down and wasting all that valuable heat, these analog thermostats can hinder any homeowners efforts to increase energy efficiency.

Digital thermostats feature two significant improvements that will make your life simpler. First, they provide a more accurate readout, which is less likely to be either misread by you or just be plain wrong. To give you an idea of just how important this is, consider the following example. A thermostat that is off by 3 degrees will increase your heating bill by between 3-7% throughout the winter! That can mean hundreds of extra dollars for some people.

Second, digital thermostats allow you to program them. No more worrying about changing the thermostat every time you leave the house! Just tell the thermostat the temperatures you want the house to be at a specific time, and viola, it’s done! What a simple and efficient way to save money.

Let’s dive into how to replace your old analog thermostat!


This one is easy, we’ll wait here until you get back from your local Koopman Lumber store with one of our great digital thermostat products.


Back? Okay let’s start!


Turn your old thermostat down all the way, then go to your breaker box and turn off switches to your furnace (and air conditioner if applicable).  If the thermostat is on electric baseboard heater, call an electrician. Sorry it ends here for you but you need an electrician to do work past this point


Start by popping off the top of your old thermostat. Most models will come right off, but some have locking screws in place. Once the cover is off of the wall-mount (or sub-base) should be exposed. Unscrew this from the wall and take a look at the wires on the back side.  Helpful Hint: Many older thermostats contain mercury thermostats contain mercury and should be disposed of properly, if not recycled.


Thermostat Terminals

When you unscrew the wall mount, you should see several wires running to the back of the old thermostat. With a piece of masking tape, label each wire according to its terminal. If you’re unsure of what that means, take a look at the photo on the right. See how each wire goes to a set screw? And how each screw has a letter next to it? These are the terminals. This is a significant step because you will need to attach the wires to the correct terminal later! Once you’re done labeling use a screwdriver to disconnect the wires. Then take another piece of masking tape and secure the wires to the wall, so they don’t slide back down behind the wall.

Note: There may be extra wires that aren’t in use and that’s OK, simply disregard them!


Take the mounting bracket from your new thermostat and place on the wall where the previous thermostat was. Feed the wires through your new sub-base and use a level to line it up on your wall. Now for this part we recommend marking the wall through the bracket’s mounting holes using a pencil. Then drill out the holes in the wall. Make sure that drill bit you use is smaller than the screws provided.

If you hit hollow space behind the wall, use the plastic anchors included with the new thermostat.  Note: Anchors are important for protecting your wall. They give the screw a secure hold where it won’t eat through your drywall or plaster with the threads and quickly loosen.


Line up the new bracket with the hole in the wall and connect the wires to the terminals. Take each wire that’s labeled and find it’s proper terminal in the new thermostat. Use a screwdriver to attach each wire to the correspondingly marked terminal. Don’t forget that you might have some extra wires. That’s still OK! Don’t attach those to anything.


With the wires attached all that’s left is to install the front. Start by adding the proper sized batteries before you place it on the wall (the packaging will have this information, but you can probably tell just by looking at it). Most thermostat fronts will just pop right on. If not, consult your users manual.


Turn your furnace and AC back on at the breaker and get ready for a new era of energy efficiency in your home. Your new thermostat will start saving you money right away. Remember that your new digital thermostat will take some getting used to, so feel free to play around with the temperature for a few days to get the feel of it. Take some time to fully explore your thermostat and get a feel for everything it can do. It may even feature some capabilities that you weren’t even aware existed, so get in there and give it a try!


Congratulations! You’re now the proud owner of a digital thermostat! Your home and your heating and cooling bills will thank you for this upgrade in due time. If you have any question or hesitations about this DIY, reach out to us online at Koopmanlumber.com, or at one of our many store locations! We hope you enjoy your new thermostat as much as we enjoy ours!

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