Does the Nest Thermostat save you money on energy bills?

By Phil Nickinson
published

There's nothing magical about the Nest Thermostat. Not really, anyway. It's a little computer bolted to your wall and connected to your home internet is all.

Metal. Plastic. Wires. Maybe some ball bearings or something. (Everything good has ball bearings. It's a scientific fact.)

So magic? No. Able to save you money on your home energy bill? Most definitely.

I've used a Nest Thermostat for years. And the thing about it is this: It knows where you are. Or, more precisely, it knows where you're not. A big part of the Nest experience (and not just the Thermostat, but across all of its products at this point) is the Home/Away Assist feature. Just like it sounds, the Nest Thermostat can tell when you're home, and when you're away. And it adjusts itself accordingly.

When I'm home, my Nest Thermostat gently adjusts itself to my specifications. I can set minimum and maximum temperatures depending on whether the heat is on, or the air conditioning is cranked. (And where I am in Florida, it's not uncommon to have to flip between the two on a daily basis.) And in between those extremes, the Nest Thermostat starts to learn where I like the temperature to be when I want it to be there — and then it does the rest.

Let a Nest Thermostat shut things down when you're not home and you'll very quickly see its worth.

I've learned not to sweat the small stuff too much. If I'm a little hot, I turn the temperature down. If it's a little cool, I'll raise the heat a degree or two. If the Nest doesn't happen to guess right 100 percent of the time, there's a pretty good chance that I'm the problem. (At least I'm pretty sure that's the case in 2018, when all of these damned gadgets are smarter than me in the first place.)

This sort of prediction can things in a more tolerable range while avoiding large swings and keeping the system on longer — which eats up a ton of energy.

But it's when I'm "Away" that the Nest Thermostat really earns its keep. You could have it switch the system of "Off," but that's not all that smart. Better would be to give it a range in which to stay. That's called "Eco" mode, and it ensures that my home doesn't get too hot or too cold while everyone's gone — but also that it's not wasting electricity keeping it perfectly comfortable while there's nobody home.

Consider: In the winter, Eco mode will let my house drop down to, say, 64 degrees when it recognizes there's nobody home. (Those of you in the North are scoffing right now, but stay with me.) Pets won't get too cold, but I also won't have to heat it up too terribly much once we return. In the summer, I'll let Eco mode get up to 78 degrees, and that way we don't have to cool off too terribly much, but neither are we wasting the A/C on an empty house.

Here's how Nest puts it:

Home/Away Assist uses your Nest products' activity sensors and your phone's location to tell when everyone has left your home. Your Nest Thermostat will wait a short while to make sure nobody's coming back, then it will switch to Eco Temperatures. When someone returns home, your thermostat will automatically switch back to your regular temperature schedule.

That's pretty basic stuff, right? It uses your phone's location in combination with the sensors on Nest products (the thermostats, Nest Protect smoke detector, and Nest cameras) to tell when you're at home. And then you've got minimums and maximums on temperature. But it's that ability to tell when we're home and when we're not that's made all the difference in the world. It means I don't have to worry about manually turning off the thermostat when I'm leaving the house. (Because I will forget. A lot.)

After even just a few months of owning a Nest Thermostat — whether you've opted for the grandaddy Nest, or the less-expensive Nest E, that sort of savings quickly becomes evident. How much you'll end up saving? Well, that's up to you. It's not magic.

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Phil Nickinson
Phil Nickinson
23 Comments
  • Also thing to look into is some areas you will get back money for buying one. I live in MD and PEPCO(Electric) gave me 100$ back on my nest e i got new on ebay for 110$
  • So as a hvac tech of 20 yrs no the nest does not save u money, i hate when people want me to install them, some systems carrier infinity, ruud premium units and many others can't fully use what they can do slow the speed of the fan when humidity is high or low depending on the call and many other reasons they are nice to look at but that's it
  • I picked up a 1st gen Nest when they first hit the streets, and while it's difficult to compare bills directly year to year, there was a definite overall trend downward in my bills. Enough that after 6 months I forked out the cash for a second one for the second floor of my house. That's where the savings really kicked in because only my kids use the second floor, and that's just for TV and game room. So no need to heat/cool all of the time. Enter the Away mode. Instead of the kids fiddling with the thermostat and not resetting it when they are done, Nest does it for them. That has resulted in significant savings. When no one is using the second floor, it auto sets to 60 in the winter and 78 in the summer. That's a big deal in terms of energy consumption throughout the month. Nest is a great investment if you use it properly, and will easily pay for itself.
  • Is this like a Nest ad? Because there's multiple thermostats that do this. I have an Ecobee 3 and it works exactly the same. I can even set up custom geo-fences so it knows when I'm "close" to home. Ecobee also has room sensors to detect if someone is home, so you don't have to rely on everyone having the app. Just stick it to the wall in a room where people may be throughout the day. I'd thought about trying a Nest, but my energy company provides an Ecobee for free. I'm happy with it. No idea if it saves me money, but it was free and at the very least it works as well as a regular thermostat. Also, if no one is home and you don't have pets, "Off" is the right choice, unless it's so cold something in your house might freeze or so hot something might melt.
  • " No idea if it saves me money" Precisely, nobody knows if this thing is ever going to pay back that money. Unless someone can do a study in a controlled environment with same house under the exact same conditions i.e same amount of heat or cold. Use a regular thermostat for 2 months and a Nest for 2 months and see if the electricity usage is any different. Otherwise there is really no way to know. You can't compare bills from previous months or years because guess what? Weather is not the same month to month or year to year. Neither is the amount of time someone is home , maybe you went on vacation for a week or 2 and you shut the a/c off. Maybe someone was sick and spent a week at home, these kinds of things. For Nest or anyone to claim that this thing pays for itself is total bs. Just market it as a cool toy, easy to use, control from your smartphone thermostat and be done with it.
  • Would avoid Ecobee until they sort out their server issues.
  • My biggest problem now is the kid's upstairs bedroom. I have a dual zone setup and have to run the whole upstairs hot to make sure her room doesn't get too cold (it's on the corner and the door is closed). There is a smart air vent product that integrates with Nest and Ecobee, but it's about $100 per vent and you'd have to retrofit the entire upstairs. Either that or just keep every other vent closed upstairs.
  • I just like the ecobee for convenience, someone is always home and turning a heat pump up more than 2° turns the heating elements on. Which you do not want. So I don't want it to think for itself because it's not that smart...just to follow my schedule ...(drop at night, raise 1° per half hour starting around 5am.)
  • It's all ball bearings these days.
    https://youtu.be/pbWWxGmbS9s
  • I had the 2nd gen Nest in my old place and it worked well enough, but I ended up putting in a Ecobee4 in current place for the remote room sensors. It works about the same as the Nest but it has a little more smarts based on room occupancy so it does a better job of balancing out the whole house rather than just the end of the hallway.
  • There seem to be quite a few people who will compare these to their own smart thermostats and mention that theirs is better or why would you buy this one. It's less about that, than just specifically mentioning that if you don't have a form of smart thermostat the Nest is a nice option. I am sure other smart thermostats do good work as well. Transitioning over to a smart thermostat system from the manual ones (if one hasn't by now) will quickly earn the money back. Also, thinking that just set schedules is the way to go and you won't get better by using a smart thermostat...well, that just seems ignorant. Some products might be adding little value in one system to another though. I wouldn't trade one smart system for another at this point to make money back. Just choose one that has good reviews and consider this one as an option if you don't have one. It's saved me good money and now that it has paid for itself, I look at it as though its paying me money every month that I don't have to spend on oil.
  • absolutely not. I'm a heating engineer and installed one at home so I could see if it saved money. I needed to fit it so I can give my customers the correct advice. My advice is, if you want to be able to control when you heating or hot water come on when you away from home then it's good. However as far as learning mode is concerned, it will learn when you get up in the morning and what temperature you want when you get up. In reality what happens is this. Assume you get up at 7am it is likely the heating comes on anything from half hour to 3 hrs before you get up, so it can be at the desired temperature when you get up, this using more gas. Most people set their heating to come on between half hour or when they get up for anything from half hour or longer.
    I hope that makes sense but please ask if you have any questions regarding use
  • i'd rather the thermostat burn the fuel moving from eco-low in the night to room temperature by the time I wake, than keep running all day with no one there. so if it uses the same overall fuel (that's a guess), at least I'm comfortable, which is the whole point of it. for me, there'd be no point in waking up and adjusting thermostat: i'll be gone before house temp changes any worthwhile amount.
  • Do you realize there are 2 different ways Nest can be programmed to begin heating? One mode begins heating exactly when it is programmed to start, the other begins heating (or cooling) so that the desired temperature is reached by the programmed start time, depending on the outside temperature and learned characteristics if the home.
  • ^this!
  • I also like my Nest, but unfortunately in the house I'm actually moving out of, it wasn't able to do a good job of using home/away to regulate temperature. Although we have dual zone heat/ac, it's all controlled by one unit (multiple thermostats). Upstairs, my master bedroom has a high cathedral ceiling. In the summer, when the nest allowed the temp to climb, the bedroom temp would quickly get to 78 but cooling it down was a nightmare. It could take 12 hours to come back down to even 72. We eventually just had to leave it set to one temp.
  • I used to use learning mode. Now its just on a schedule. A pretty boring one: eco range and normal range. That's it. I've given up on trying to let the temperature lower much in the winter--because I'd rather burn some fuel and have a few more precious hours or minutes for when/if a failure occurs to do something before pipes freeze and then all those savings would be long gone.
  • As a certified electrician and hvac tech, I can tell you that whether or not you save energy depends on the temperature spread over a specified time in home and away mode. For instance, if you drop the temp by more than 3 degrees and then 4 hours later return home and raise the temp back to the original setting, more energy will be used than if the temp had never been changed. Over an 8 hour period, a temp change of 3-5 degrees "might" save energy but even that depends on the type system your home is equipped with...heat pump, electric, gas, etc. Just because the system does not run for a specified time does not save energy if it actually has to run longer in the short run to bring the temp back up or down to desired setting. Its a fine balance but savings can be achieved by increments of 2-3 degrees (but not more). I will also ad that for the "average" home and occupancy, it will literally take 8-10 years for a Nest or other smart thermostat ($300) to pay for itself...
  • Plus if you leave for a couple hours, when you get home your house is a few degrees warmer or colder because it triggered eco temps which is less comfortable than the house just staying in the desired temperature range. However if you carefully manage your away (eco) temps, it can be a good thing. In FL where it heats up like crazy during the day, I think it's good because I keep it cold at night around 70 and let it rise naturally to around 76 which is still a comfortable temp when I get home. That allows the system to barely run during the day while after 6pm and the weather is cooler it doesn't work as hard to bring it back down and my old system would have run 90% of the day to maintain 70 if I ever forgot to turn it off. I used to set my ECO temps to around 80 degrees but when I got home my house was hot and it would run non stop for several hours to get it back to 70. Had to find the sweet spot of how much energy it took to get it back cool vs running at a constant temp all day. For the super savers out there like me, I would just as well have a notification from the nest telling me it was going into eco and asking how long I was going to be away with a few options. That way if I said 2 hours it wouldn't turn off the system but if I said 12hrs it would do a more hardcore eco cycle
  • I don't know about Nest thermostat, but the ecobee4 with room sensor does keep the temperature at comfortable level depending on where I'm at any given time. And yes it also has the home and stay mode and it kicks in quite well.
  • I actually haven't paid attention to whether I've saved money. I bought my Ecobee3 soon after I moved into my house, so I don't have anything to compare it to. I will say the room sensors do a good job at keeping the house comfortable. My rooms do not heat/cool evenly at all.
  • My Nest sucks. It has over 2 degrees F of tolerance (or whatever term you want to give it). It gets cold in the house, about 2 degrees colder then it is set to. Then it runs the heat, and runs and runs. Until it gets too hot. Same in the summer with the AC. It gets way to hot, then finally kicks on and run and runs too long and gets too cold. Occasionally the WiFi in the unit goes nuts and makes the thermostat warm, that really screws the sensor up. If I wasn't so cheap I would get an EcoBee and toss it in the drawer.
  • You lost me when you said " 64 degrees "