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
Very similar to my situation ... Have a home originally built in 1912 (Sheesh, the year the Titanic sank ...lol). Which has an old two wire gas furnace. Installed a Nest gen. 3 like in the video several weeks ago, which appears to be working fine so far without a C wire. But since I read several comments that this could still cause problems later on, but running a C wire is too much of a hassle and didn't want the unsightly dangling wires of a plugin AC/AC adapter at the thermostat. Installed the new "Nest Power Connector" at the furnace that converts to two thermostat wires, R and W, into three, an R, W, and C wire. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-xlx2Um6D1Z8.html
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!
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.
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.
I have an Ecobee in my apartment. A dedicated 24 VAC transformer plugged in near the thermostat does the trick. You don't need a C wire for it to work, but without one you will need a dedicated power source!
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.
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.
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.
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. 😉
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!
I'm sure they are fine for some simple installations. But for how much they cost and the problems people have had so far with them. Google nest updated causes no heat during ice storm. They've also caused alot of heat pumps to use more electricity by using aux heat strips to recover temperature. Also if you have a high seer system with bells and whistles, you are most likely better off using that systems recommended tstat. Its possible they have improved but they caused so many issues at launch and for a while after it is hard to recommend them to anyone.
Nice video. I have an old Coleman floor furnace. Probably at least 60 years old. Thermostat is mercury switch with only 2 wires. How do i know where to connect wires on a smart thermostat? Thx. Marty
you dont. your wiring is too old to work with this. the only way would be to replace the furnace and put in all new wires, which obviously wouldnt be worth it unless the furnace was already broken and needed replacing. you are kinda stuck with what you got.
I have an inconsistent work schedule. The Nest gen3 also has geo-fencing which is kind of cool. Say you're within a certain distance of heading home, you can have it adjust to your comfort temp before arriving. Same with going out. Or you can just use the app on the fly. It uses your phone's GPS.
In these it's in an IC chip that turns it on and off. On Dumb ones it's a coiled piece of tungsten that moves enough with changes in temperature to trigger one relay to the left or right and the temp set adjusts where they point is.
A large amount of people see these online, at Home Depot, Lowes, etc. and think that they will automatically work for their home application. This is not always the case. In many instances; Particularly with homes that have oil or gas fired heating systems and no central air conditioning they will have thermostats running off of only two wires. A red and a white. These smart thermostats, specifically the Nest thermostats, want to have 24 volts of electricity provided to them via a transformer. In the case of just a red and a white wire you will not be providing adequate voltage to the thermostat and it will end up running off of the internal battery. The battery in these thermostats exists to maintain settings during a power outage or during electrical work where power would be turned off for your equipment. You may experience problems with your smart thermostat if you attempt to install it without proper wiring. It's important to know what you have before you go out and spend $200+ on a smart thermostat or you should be at least prepared to have a transformer installed alongside replacing the thermostat wires if needed.
You can, but should you? I've been to several customer's houses where they've had complaints about the longevity of the thermostat's battery as well as issues using wifi on the thermostat because of low battery voltage as a direct result of not having a dedicated 24v provided to the thermostat. The thermostat will only charge when the unit is running. In this case, if the unit is not run frequently enough, the Nest thermostat may even simulate a call for heat for a very brief period - in pulses - as a last resort. It can only charge itself with a bridged connection - AKA when there is a call for heat, so 2 wire setups with less frequent usage on their equipment are prone to suffering from battery issues. The "pulsing" of your equipment in most cases would be fine, but in some instances it may result in damage and/or a noticeable amount of noise. So just because it's possible to run them on only a red and white wire doesn't mean that you should.
I just installed the gen3 Nest today and didn't have a common wire. I was going to call someone to help with this, but looked at one of their instructional videos and it said it might work with what I had. I have the yellow, red, white, and green wires. So I gave it a try and it seems to be working fine. This is an older Rheme AC with heat when needed. (Florida). Would I run into the same problem you're describing? Just curious.
question about the motion detection in the house im in, the thermostat is mounted on a wall nobody walks by it is in a room that is not used much facing into the room so how will this effect it ?
It will think no one is home. However there is a solution for this. Two of them. The first one is easy, Nest now makes individual room sensors that connect to the main Nest thermostat, buy one sensor and put it right in your living room. Problem solved. You can even have one in each room, so it keeps the occupied rooms at the set temperature and ignores the the temperature of the unoccupied rooms. The second option is to relocate the wall that you mount your thermostat on, is a fairly easy job, something you can do yourself.
My existing thermostat has 2 wires. Red and White for heat only. Nest 2020 requires C wire. If I use a transformer, where do I connect the wires transformer wires? Nest 2020 has O/B, G, Y, C, R, W terminals.
I am interested in installing this in my house but we have 3 different thermostat controls , 1 in the basement , 1 on the main level and one in the basement so my question is do all 3 need to be replaced or just the one on the main level that is digital?
After watching this show, I bought the Nest thermostat and I was able to install it myself. We keep getting this Error ( WIRING REPORT E74 ) with no power to the RH wire. We have taken all the wires out and rewired it again. We still get the same error. Do you have any ideas or suggestions for fixing this issue?
You don't NEED wifi, you can use it like a good ol' thermostat by adjusting physically. It's super convenient when you connect to wifi and can remote access your thermostat.
You can set it to do that, if you want. It's recommended for areas where you have large temperature variations between day and night, such as desert climates.
I got a smart thermostat, Trane XL 950. But now it has never been updated. When I purchased it, the instructions said it could be updated on line. but no more. Now they want you to call a local Trane dealer and have him update it. All it takes is an SD card. The dealer downloads the program on the card and comes and puts it in the thermostat, Thats it. But I can't do that. Help
Isnt 55 terribly cold. I keep the house between 67 when I'm gone and 70 to 71 when I'm here. Do folks really set to so much cooler in the day while at work ?
My Lennox wifi thermostat replacement cost me a little less than 900 hundred dollars,trip charge,with condenser washed,check freon (none added) ,warranty 5 years(not very good)
I really like how they took the nest instructional video and then covered the exact same scenario while also unnecessarily making the video a lot longer.
Ours has become a total nightmare, heating and cooling guy told me to get rid of it. Way to sensitive to power fluctuations. The other day the display was flashing "touch yourself", very hackable
Great video. I only had one question. I wish he broke out a multi meter to test the voltage for the common wire. Newer Nests require a C wire aka common wire. Old homes may not have that. Thank you. Great video all the same. Now get the paint. lol.
R is not heat. W is not fan. Here is the correct colors: R is power supply, ie the hot wire. You can touch this wire to any of the other wires to complete the circuit and request that function to be on. Y is for cooling. W is for heating. G is for fan. But be careful with C (black) and never touch R to C as that would be a dead short between hot and common and blow the fuse.
sometimes they have a kit that you have to connect to inside the furnace itself. Not sure about Nest but Echobee has a kit with its thermostat if you don't have a C wire.
Seems so easy in this video but these things are a nightmare to hook up especially if there's no C-wire for constant power supply. Two wire systems are absolute nightmare for Nest thermostat installation.
Unfortunately I have a boiler/radiant heat system which requires you to set your temp and forget it. I always wanted a Nest, but it would just be a big waste of money for me :-(
Technically, the Nest doesn't require one but it's highly recommended. It you don't have one, the Nest will attempt to charge by running your blower and charging off that, but doing so will waste lots of energy. You can get around this by periodically popping it off the base and charging it via micro USB, but I doubt you want to do that regularly.
