How to Replace an Old Thermostat -- by Home Repair Tutor
Thermostat Wiring for Dummies
In this how-to video, This Old House plumbing and heating contractor Richard Trethewey shows how to install an automatic, fully programmable thermostat. How to Install a Digital Thermostat. Many older homes have outdated thermostats in which you turn a knob to set it to the desired temperature. These old thermostats can be inefficient and cause heating and cooling bills to rise. Upgrading. Wiring Set-Up Explained. What I would like you to know is the information detailed below is based on the industry standard, yet not all thermostats will work this way simply because letters and numbers are used as well as color. Plus, I'm anything but a technician so what I have detailed below is here purely as a guideline.
I'd like to put in a new programmable thermostat to better control my energy costs.
DIY – How to install a Digital Thermostat
Can I install it myself? More expensive products, such as the Honeywell Prestige that I installed here, handle many more functions, including cooling and humidifying. Typically they're purchased through and installed by HVAC contractors, but you can also buy them online. Before you buy a replacement thermostat, however, take a peek at your existing wiring.
If there are only two wires, the simplest solution is to get a replacement with a battery-powered display. Full-featured devices like the Prestige need power from a third wire, something best installed by an HVAC or electrical contractor.
Cut off power to the furnace using the emergency shutoff or breaker switch, then unscrew the thermostat's mounting bracket. As you disconnect each wire from its terminal, label the wire with the letter of the terminal it came from.
Before you buy a replacement thermostat, however, take a peek at your existing wiring. If not, consult your users manual. If the hot wires comes from the cooling system then you should use that common.
Tape the wires to the wall so that you don't lose them. Some older thermostats contain mercury; for information on proper disposal, go to the Thermostat Recycling Corporation.
How to Install an Energy-Saving Programmable Thermostat | This Old House
Line up the new bracket with the hole in the wall, and connect the wires to the terminals on the bracket, following the diagram in the instructions. This thermostat needs at least three low-voltage wires: If you have only two wires, call an electrician or HVAC contractor to run the additional or gauge wire. Let your contractor hook up the new wire to the furnace and turn on the furnace's power.
Now snap the thermostat's face onto the bracket. When it lights up, follow the prompts to set the temperatures you want the house to be when you wake up, leave for work, return home, and go to bed. This wireless, battery-powered device allows the thermostat to display outside temperatures. Turn it on while standing next to the thermostat.
When both units establish a connection, place the sensor in a bracket mounted on the north side of the house, above the snow line. Skip to main content.
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Save on your energy bill with controls that automatically change the temperature settings. Photo by Ryan Benyi. But if additional wires are needed, hire a contractor. Want to hire a pro for this project? This Old House has partnered with HomeAdvisor to connect you with trusted home improvement pros!
We hope you enjoy your new here as much as we enjoy ours! Line up the new bracket with the hole in the wall, and connect the wires to the terminals on the bracket, following the diagram in the instructions. The first thing you should do before changing the thermostat is to select the proper thermostat for your system.
More in Heating The latest energy-saving devices can talk to your power company — and you. Shopping for Smart Thermostats. Figuring out which grippers are best for the job. Choosing and Using Pliers.
Thermostat Wiring Made Simple - Online hookups!
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