To Nest or not to Nest. That is the question.
January 29, 2021 9:37 AM   Subscribe

We have a very old thermostat and are looking to replace it. The Nest is

interesting, but I expect that we don't have the C wire. Plus, there are too many variations of Nest, which do I want? I also see Ecco Bee which seems to do everything that a Nest will without the C wire, is that correct? This is an electrician job not an HVAC job, correct? What question should I have asked?
posted by notned to Home & Garden (23 answers total) 6 users marked this as a favorite
I installed a Nest at our last house and it was a total game changer. Having the ability to make the house a little warmer without having to get out of bed is amazing. Leaving the A/C off while you're on vacation and turning it on before you board your flight home rocks. Our install was very easy; it took maybe 5 minutes, but our thermostat was ~10 years old at the time.

According to this site, they make this gadget that will give you a C wire.

I think you can do this youself, but if you don't feel confident with it, a quick call to an HVAC technician or an electrician should be able to tell you if they'll do it for you and how much it'll cost.
posted by spikeleemajortomdickandharryconnickjrmints at 10:00 AM on January 29

We do not have a C wire and our Nest works without any problem but I have heard of others whose furnace cycles on and off constantly. Maybe it has to do with the fact that we have a boiler, not a furnace, so heat only. I have no idea. I wanted to get rid of the Nest because of Google (we have had ours for several years and Google was not at that point insisting on using a Google account; I didn’t even know that Google had already bought Nest). My preference was ecobee but as far as I could figure out, all of their models require a C wire. Ecobee makes an adapter available which may work for your furnace but that installation must be done by an electrician. Going back to Nest: it doesn’t matter which version you choose because the connections are the same - choose the one that meets your needs and budget - if you do the 2-wire installation (you can also go the adapter route with a Nest), attaching the two wires is easy. The instructions will tell you to make note of which wires you have and which wire to connect to which terminal.
posted by strasbourg at 10:05 AM on January 29

I have installed both, and neither require an electrician or an HVAC specialist. Installation is straightforward and simple.

A warning on the Nest: We had two furnace motor circuit boards short circuit and require replacement. The HVAC teams that did the work said that it was because of the Nest and its tendency to send an incorrect signal to the furnace (I'm not an electrical expert and am likely explaining this poorly), and that it was a not uncommon issue they were seeing. Their feedback was echoed by another technician I spoke with about the issue. Both recommended replacing the Nest with Ecobee, which I did, and have not had any problems since.
posted by NotMyselfRightNow at 10:07 AM on January 29 [2 favorites]

I installed our Nest thermostat myself. You can probably figure out if you have a C wire just by looking at the wiring terminal on the thermostat you have now. Every single one I've ever seen has all the different attachments marked. We had a C wire, and our Nest worked just fine with our heat pump. When that died and we replaced it with a gas furnace and AC, I just went through the equipment setup part of the Nest app, and it has continued to work fine.

If I were buying one now I might buy an Ecobee, partly because of Google and partly because Ecobee was ahead of Nest with the idea of room sensors that didn't also have to be full thermostats. Nest eventually introduced a temperature sensor for this purpose, but we'd have to upgrade our thermostat just to be able to use one. If I'm going to have to buy a new thermostat just to use a feature that honestly should have been integrated in the one we have, that also turns me off the brand a bit.
posted by fedward at 10:21 AM on January 29

So I suspect if you really lack a C wire you don't have a standard 24V furnace controller system. If you have a common furnace that uses a 24V control, you definitely have a C wire somewhere. So the issue is less the one wire but figuring out whether you have a millivolt control system or whatever.

The C is the "Common" wire for all the control relays and the Ecobee is going to need it just as much as the Nest does for 24V control systems.

This guide lists all the different types of wiring configurations the Nest Learning Thermostat supports.

There's a newer "Nest Thermostat" which is cheaper and simpler versus the older "Nest Learning Thermostat" but I think the older one is better value and the dial control is better than the touch control on the new one.
posted by GuyZero at 10:34 AM on January 29

I love our Ecobee. My husband installed in like 4 years ago himself, set up how we want it and until we started working from home last year I have never had to touch it.

The only thing I did when we started WFH was to remove the "Away" setting that ran during the day on weekdays since we're just always Home or Sleep now. Took like 3 seconds.

I love this thing.
posted by magnetsphere at 10:34 AM on January 29

I asked a similar question. I did buy and install the Nest E thermostat. There may be others now that don't require the C wire, but this did not. My furnace is at least 25 years old. I have a remote sensor that is handy. It doesn't do a good job of predicting; I just have it on a schedule. Nice to be able to check the temp from elsewhere.
posted by theora55 at 10:38 AM on January 29

I think the Nest I have is the Nest E - it doesn't require a C wire. Before that we had a Honeywell wifi thermostat which I also liked but I can't remember what kind of wires it needed (this was at a previous apartment). They were both easy to install.

My gas company routinely offers $100 rebates on wifi thermostats, which is about what either of these thermostats cost (and sometimes you can even buy them directly from the power company for like $5, or get an instant rebate at Home Depot though I don't know how that works). Check to see whether you have something like that available to you!

And I agree, I love having a wifi thermostat. So much easier to program, and so great to be able to adjust the heat from wherever (I went on a trip last week and forgot to turn down the heat before I left, so I was able to adjust it as soon as I remembered; then fortunately I DID remember to turn the heat back on a few hours before I came home because I have steam radiators that take a while to do their business).
posted by mskyle at 10:46 AM on January 29 [1 favorite]

I also see Ecco Bee which seems to do everything that a Nest will without the C wire, is that correct?

The C is the "Common" wire for all the control relays and the Ecobee is going to need it just as much as the Nest does for 24V control systems.

Ecobees come with something called the Power Extender Kit (PEK) that you install at the furnace. It allows you to power the Ecobee from the existing wiring in your walls without adding the C wire.

Installing the PEK does involve opening the furnace and unscrewing the connections, so keep that in mind. Here's how the installation looks.
posted by JoeZydeco at 10:49 AM on January 29 [1 favorite]

I have a Nest. Came with the home we bought. I like it.

However, after reading up on some of this, I think I'd choose an Eco Bee. Reason is, you can get remote thermometer sensors for an Eco Bee. Why is this good? Well, our Nest thermostat works great, but is installed in a stupid area, a small hallway across from a guest bathroom that often gets too warm (the vent/register is broken). So the Nest controls the temp of our entire split-level home (a duplex-down condo) based on a dumb location. This means our main bedroom will be cold, because the Nest thinks it's warm enough based on its location.

If we had an Eco Bee, we could place a remote thermometer sensor in our bedroom, which would tell the main thermostat the temperature that's important to us. I think you can use a few of these and put them in key living spaces and program around them based on time of day (bedroom warm at night, rest of home cooler at night, etc.)

I'd at least read up on these factors with the Eco Bee, and think about where your thermostat is located.

That said, the Nest is fine, and yes it's nice to be able to change the temperature with the app or my laptop browser. A remote sensor would be much better and I don't think Nest does those yet.
posted by SoberHighland at 10:58 AM on January 29 [1 favorite]

Nest does offer remote temperature sensors now, whereas Ecobee has always had them and you get 1 free except with the Lite models IIRC.

Something to note with Ecobee is that the system will average the temperatures across ALL sensors connected to the base unit unless you tell it otherwise. You can program different sensors to be active during certain programs. New owners sometimes report strange heating/cooling performance across the house until they realize what is going on.
posted by JoeZydeco at 11:01 AM on January 29 [1 favorite]

To add to that, if you want remote temperature sensors you will need a recent version of the more expensive "Nest Learning Thermostat." The remote temperature sensors are not supported by the cheaper "Nest Thermostat" or by the older model we have (which I installed in 2013). Since Ecobee has supported remote sensors for longer, that means you can often find discounts on previous Ecobee models with remote sensors included.
posted by fedward at 11:07 AM on January 29

I have a Nest E that said it didn't require a C wire, but it wouldn't work without one (and didn't give clear errors, it just wouldn't stay on). There was a place to connect the C wire in my furnace, so I just turned off power to the furnace, connected the wires, and now it works fine. Search for your furnace manual but it should be pretty straightforward, there were slots labeled with the same letters as the thermostat.

I have been unable to get the Nest app to use my iPhone to tell when I'm away, which is annoying, but my old thermostat wasn't programmable so it's still a step up. Check your utility providers for credits to buy a smart thermostat, I got $100 off.
posted by momus_window at 11:53 AM on January 29

I have a Nest and a Remote Sensor was added as a freebie. It isn't quite reliable, but I can sort of tell it to use the remote sensor, which is upstairs, instead of the main thermostat on the 1st floor. My desk is upstairs right now, so this has been handy.
posted by theora55 at 12:48 PM on January 29

We love our Ecobee. Misterben installed it himself.
posted by matildaben at 12:49 PM on January 29

FYI: Nest has Temperature Sensors that you can put in individual rooms and use to prioritize different spaces.

We have the Nest Learning Thermostat, ours was installed by our HVAC installer because we wanted to change the location of thermostat. This was a dumb choice, as we relocated it to an area of the house which is warmer than all others, but I was just complaining about this to a colleague who recently self-installed their Nest thermostat and let me know that these sensors exist.
posted by sm1tten at 12:52 PM on January 29

We used a Nest for about a year and a half. Just recently we had to replace our furnace and as part of the install they replaced our Nest with an Ecobee. It is a job for an electrician.

Aesthetically, the Ecobee is slightly worse than the Nest. The thermostat and app have kind of an awkward UI, but it's not impossible and it gets the job done.

There are a few nice things about Nests (they look great), but the 'learning' feature of the Nest was absolutely terrible. We were constantly battling the thermostat to get the temperature right... it never correctly learned what temperatures we wanted, adjusting the schedule it had learned was very difficult, and it just never did exactly what you told it. Even trying to turn off the learning features didn't seem to help. This was probably made worse since our house is pretty drafty and gets cold quickly. I don't miss it and wouldn't recommend getting one.
posted by TurnKey at 12:55 PM on January 29

We have a Nest and I really like it - it’s great to be able to adjust the temperature without getting up, check the temperature when not at home, etc. I installed it myself - it was very simple - I’ve never installed a thermostat before. We don’t have a c wire and it’s been 99% fine, except that during a polar vortex it kept turning off. We disconnected the a/c wire (see info here) and it has worked fine since! We reconnected that wire at the beginning of the summer and have left it connected since. In case it’s helpful, our lowest winter temperatures are usually in the single digits Fahrenheit and the Nest has been fine; I don’t remember the temperature where it started having problems, but it was well below 0.

I also didn’t find the learning feature helpful, so I turned it off and it’s been fine. I did find the feature where it knows when you’re home (based on cell location data) helpful pre-pandemic, though someone is always home now so that’s less useful. I have a set schedule and I like that it’s easy to adjust both the current temperature and the schedule.

My only hesitation in recommending the Nest is that Google just bought it - so if you are concerned about big tech companies having even more info about you, that might be one thing to keep in mind.
posted by insectosaurus at 4:54 PM on January 29

Just echoing that I installed an ecobee about three years ago and we love it. Being able to shout at a smart speaker to adjust the thermostat is pretty awesome, as is having multiple sensors around the house.
posted by WedgedPiano at 7:17 PM on January 29

My experience with the Nest was very similar to TurnKey’s. I found the thing absolutely infuriating. We have an Ecobee now, and it’s fine. I don’t use any smart features (I’m kind of burned out on smart devices), but it doesn’t act like a drunk toddler in the way that the Nest did. My husband had to run new wiring to the boiler for the Ecobee — I’d recommend an electrician, unless you’re pretty capable at wiring.
posted by another zebra at 6:39 AM on January 30

Nest is a bad product. I'm glad for all the folks here who've had good experiences. Me and my friends, we've had years of broken product updates, malfunctioning websites and apps, and the occasionally fully bricked device.

Ecobee seems to be the popular choice for an alternative.
posted by Nelson at 9:39 AM on January 30

It might help if you could provide a bit more information.

1. Does your thermostat only handle heat or heat plus air conditioning?

2. Does your thermostat have a separate control for the fan to circulate air?

3. Can you pop the thermostat off the wall and see how many wires are connected and their letters on the terminals? Typically R, C, W, Y, G among others.

4. Are there any unconnected spare wires? These might be folded and bent back into the wall cavity.
posted by JackFlash at 10:31 AM on January 30

JackFlash's point #4 is a good one. When we moved in here 15+ years ago I made due with the cheap, hard to program, battery powered thermostats. The C-Wire wasn't hooked up so I didn't want to invest in a smart thermostat. Eventually we had some preventative maintenance done on the furnace and I asked about the C-wire hookup. The furnace guy was able to do it cheaply and easily because there was some unused wire pairs in the wall.

I've been pretty happy with my ecobee.
posted by mmascolino at 10:50 AM on January 30

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