How to install set-back thermostats to save on your heating and cooling costs.  A few weeks ago we covered smart thermostats. Today we will cover the more conventional setback thermostat. Would you like to save money on your heating and cooling monthly bills?  Well, who wouldn’t…! Thermostats control heating and cooling appliances in our homes.  A setback thermostat gives you the option of changing the temperature setting automatically at night and also during the workday when you might be away from the house.  A setback thermostat can help reduce overall household energy consumption.

Quick Stats on Thermostats

A conventional thermostat simply regulates house heating at one temperature.  For instance, in the winter, if you set the thermostat to 68°F (20°C), it will activate the heating system when the house temperature drops below 68°F and will shut the system off when the house air warms up past 68° F.

A setback thermostat contains a digital clock.  It can automatically turn down the temperature setting on the variables you set.  It can also return the temperature to a more comfortable level before you wake up or arrive home from work.  That way, you can have the energy savings of a lowered thermostat setting without the discomfort of having to wait for the house to heat up again.

The setback thermostat can also be used as a set-forward thermostat for an air-conditioning system.  It can allow the house to heat up when it is unoccupied and return it to a comfortable temperature before occupants return from any daytime activities.

How to Install or Replace a Setback Thermostat

The first thing you will want to do is to make sure your new thermostat is compatible with your heating and cooling system; installation might differ by model and type of system in your home.

What Type of Heating and Cooling System do I Have?  You may have a gas furnace, electric baseboard, oil fired with a boiler or a heat pump based system (to name but a few).  It may sound complicated but once you know what type of system you have there are only three different thermostats from which to choose.

  • Low voltage systems are the most common systems today and only require a 24v power supply.  On average, most thermostats will work with low voltage systems.
  • Direct line (high voltage systems) use a 110v to 240v power source.  These are typically a kind of other electric heating systems. Not all thermostats will work with this, so keep an eye out.  In some of the older homes, direct line voltage is used to power the thermostat.
  • 24 millivolt systems are usually gas or oil powered furnaces that don’t use electricity, wall or floor type.


You will more than likely come across the terms “one stage” and “two-stage”.

  • Stage one heat and cool means you have units that work either at full capacity or not at all, it’s like an on/off switch.
  • Stage two (or multi-stage) means your system is capable of heating and cooling on both low and high speeds.

There are ways you can check what both the type of system you have and how many stages it is. You’ll need to look inside your current thermostat first, as it will give you the information you need. If you’re not sure, the best thing to do is ask a technician to help.  Proudfoot Plumbing, Heating & Air would be glad to assist with this.

Once You Know What Type of System You Have and What Stage It Is, Its Time to Replace the Thermostat

First turn off the old unit, and then turn off the power to your heating and cooling system at the main fuse or circuit box.

Remove the existing thermostat by first removing the cover.  Some units have locking screws and some simply snap on & off.  Leave the wall plate in place for now so you can note how the wires are connected.  Test the wires with a circuit tester to verify the power is off.  Circuit testers can be purchased online or at most any major hardware store like Home Depot or Lowe’s.


Older thermostats with glass tubes contain mercury.  Use caution when handling and check with your local recycling company for disposal instructions.

Label each wire on your existing system with the letter designation of the terminal to which it’s connected. Ignore the wire color; use only letters to identify the wires.  Your new thermostat may come with pre-printed labels for this step.  For systems that have more than one stage for cooling, look out for wires that are attached to “y1” and “y2” terminals.  The same applies to a two stage furnace.  If you have this, there will be wires attached to the “w1” and “w2” terminals.

Take a picture of the existing connections so you’ll have it as a visual reference later if you need it.

Disconnect the wires and remove the existing wall plate.  Remove it from the wall by unscrewing the mounting hardware.

Important to Know: 

Secure the wires to keep them from falling back into the wall. You can wrap them around a pencil or tape them to the wall.

Depending on the shape and size of your new thermostat, you may need to remove the old wall anchors and patch the holes. You can go to “Removing Unwanted Wall Anchors” for instructions on how to do this.

Install the new wall plate that came with your new thermostat.  Use a level and mark the location for the mounting holes.  Drill the holes and, if needed, insert drywall anchors.  Feed the wires through the wall plate and fasten the plate to the wall.  Again, secure the wires so they don’t fall back into the wall.

Follow the instructions that came with your new unit and use your labels on the wires to determine the proper connections to the terminals.  Insert the wires into the corresponding terminals on the thermostat and tighten the terminal screws.


There may be a metal jumper connecting the R and “Rc” terminals on the new thermostat.  The manufacturer’s instructions/manual for the thermostat should direct you as to whether to leave it in place or remove it (Wi-Fi thermostats may require a C wire; if you don’t have a C wire, you’ll have to consult the thermostat’s instruction manual for options).

Install batteries of the proper size as needed.  Mount the new thermostat onto the wall plate as per the manufacturer’s instructions.

Now, restore power and set up the new thermostat, also according to the manufacturer’s instruction manual.

For further clarification, please view the youtube video by going to the link that follows, now that you’ve read the above.

What Temperature Should I Set Back the Thermostat?

The more you reduce the thermostat setting, the greater the possibility for savings.  Every degree you cut back over an 8 hour period should save you 1% on your heating bill.  Generally, a drop of about 3.5°F (2°C) will lead to some savings and should still be relatively comfortable.  Some householders reduce temperatures as much as 7°F – 11°F (4°C – 6°C); however, temperature differences this large could create potential comfort and moisture problems.  What you choose to do is entirely up to you!

Please know that if you have problems with your set back thermostat installation, you can always give Proudfoot a call at 412 461 2198 or simply contact us. We will be glad to assist you with any of your needs!

Schedule Service

At Proudfoot Plumbing, Heating, and Air, we are here to help you and are happy to process your scheduling request by email if that is your preference. Please indicate what service area you require in your request, and we will get back to you within one business day of receiving it.

Contact Us from Proudfoot Plumbing