How to Install a Smart Thermostat | Ask This Old House

Plumbing and heating expert Richard Trethewey shows a homeowner how to install and operate an energy-saving smart thermostat. (See below for a shopping list, tools, and steps.)

Shopping List for How to Install a Smart Thermostat:

Tools List for How to Install a Smart Thermostat:

Steps for How to Install a Smart Thermostat:
1. Turn off the service switch on the side of the furnace.
2. Remove the faceplate from the existing thermostat.
3. Take a digital photograph of the wire connections.
4. Use a screwdriver to loosen the screw terminals on the thermostat's base plate.
5. Pull the end of each wire out of the terminal.
6. Unscrew and remove the base plate from the wall.
7. Screw the base plate of the new smart thermostat to the wall. Be sure the base plate is level.
8. Connect each wire to the appropriate terminal on the base plate. If necessary, refer to the photograph taken in Step 3.
9. Snap the smart thermostat onto the base plate.
10. Turn on the service switch at the furnace.
11. At the thermostat, follow the touch-screen prompts to choose the preferred language and internet setting, which allows you to control the thermostat remotely from a tablet or smart phone.
12. Next, enter the year when house was last remodeled, then select a name for the thermostat.[
13. Select the lowest and highest room temperatures for when you're not at home.
14. Adjust the thermostat setting each time you leave for work and return home. After a few days, the thermostat will learn your habits and automatically adjust the heat.

He also demonstrated the Nest app, which is available on select smart phone and tablet platforms.

About Ask This Old House TV:
Homeowners have a virtual truckload of questions for us on smaller projects, and we're ready to answer. Ask This Old House solves the steady stream of home improvement problems faced by our viewers—and we make house calls! Ask This Old House features some familiar faces from This Old House, including Kevin O'Connor, general contractor Tom Silva, plumbing and heating expert Richard Trethewey, and landscape contractor Roger Cook.

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How to Install a Smart Thermostat | Ask This Old House

[Percussiongurl]

This this old house still coming in clutch!! I remember watching this with my parents when was a kid now at 32 its just me.

[trypanoma]

I installed a nest learning thermostst in my parents 100 year old house with 2 wire heating system. The system worked well for a few weeks but it drove the boiler haywire as the thermostat was trying to steal power by turning it on and off. There was no c wire from the boiler. After researching, I purchased a external c wire power adapter from amazon and it worked like a charm. Almost 2 years gone and no trouble anymore. Wanted to share the experience because it took me a lot of digging. Installing a c wire was too complicated. This was a easy fix

[hsabic]

1:30 Hey the cameramen was in basement already. Why he didn't flip the switch to off.

[electricianron_New_Jersey]

This video showed me everything I needed to know. Then again I've come to expect professional demonstration from the pros at This Old House. Thanks Richard!

[mjcintx]

I like how he let her touch the wires first to make sure the power was off lol!!!

[RandomYoutuber]

I've installed the nest and ecobee units at my home and for family. It is imperative to find a way to supply power via the "C" wire. That is needed because these electronic units don't have replaceable batteries. When the Li-ion battery dips in voltage below 3.16V, it goes haywire, and in my case it started to blow the fan inside my house with the outside temperature at 22 degrees. The pipes nearly froze. I connected the C +24V dedicated supply and it has worked flawlessly for many years now.

[laghmanee]

Best video and after watching this, it took me 15 minutes each to install two of them in my house.

[JohnDoe-hfxu]

Amazing! Not complicated to install at all just basic thermostat wiring. Great video!

[RandomYoutuber]

I've had 2 of these in my house. I've installed 3 more at my family's houses. These nest thermostat have non replaceable Lithium Ion batteries. You must connect the "C" wire to a dedicated 24V supply on the furnace. Otherwise it tries to siphon electricity from the other wires when voltage dips around 3.7V on the battery. It will send the furnace into a tailspin during winter time with the blower fan going non stop. Easy recipe for frozen pipes in the winter.

[jrhrsr]

Man I have had mine for nearly over 5 years. Welcome to the 21st century This Old House!

[carnagex]

a couple years ago we switch energy companies and they offered this exact thermostat controller for free. honesty it's amazing and has dropped energy bill by a lot.

[bradfuller]

I’m surprised you guys didn’t speak about when you have high voltage, 120V, compared to low voltage, 24V, that are needed for smart thermostats. Are their any options in the smart thermostat range in the 120v range? If not how do I install a 24V transformer on my furnace or HVAC unit in order to be able to convert from a mechanical thermostat to a smart thermostat.

Maybe a good chance for an update video as these thermostats are gaining more popularity as technology and smart homes progress. Ppl will inevitably have to convert voltage in their older home.

[mauriceclemens]

The Nest is what I have in my house and it was so easy to install. Incredible piece of technology. Saved me a bunch the next year.

[jameshawkins]

I need to invest in one of these for my new home. I get tired of having to adjust the temperature all the time. This would save me a lot of money for sure.

[rupe]

This may seem a few bubbles off plumb but read a bit further... I see issues with these all the time when used in a heating / cooling situation on a home equipped with a stand by generator. The problem happens when the power goes out and someone has wired the t-stat to grab it's 24 volts from the AC side, which is usually not connected to the gen set. Ok, so it's winter and I get the call that there's no heat so the customer thinks we screwed up and didn't connect the boiler or furnace. I verify that's connected but the t-stat is a recent addition and THAT is not wired correctly. Typically someone swapped the RH (heat) with the RC (cool) wire so basically the t-stat has no power when the house is running on the gen set. (but they are both hot when utility is present so doesn't matter) Reading further.... oh, the Wi-Fi part is not working during a power failure and I have to ask where that other router is and if the cable internet is even working in this crappy weather. Some people want wireless remote control no matter what...and it ain't gonna happen! You want fewer problems? Keep everything on the simple side!

[TreesOnTheBeach]

The Nest is the best thermostat I've ever had. I have it in two houses and love it.

[Affanaman]

I watched this video and other bunch to install my smart thermostat, but it didn't fix the problem because like this guy said to install the wires as color patterns. Unfortunately, in my case, I took the picture of the wire how it was attached before removing from the old one. Thanks to this person who showed to take the picture and which I did. First, I installed like the color patterned and it did not work and my house was getting cold 9 at night. I followed the picture of the wire from the old thermostat and put it the way on the new one and my heater started working. 😉

[robertvalitsky]

He is a true genius jack of all trades

[chicanopridealvarez]

Can you adjust with cell phone WiFi when not at home?

[charliegra]

I am a commercial a/c tech and would recommend staying away from the nest t-stat.