TechStuff Classic: TechStuff Adjusts the Thermostat

up the heat and talk about thermostat technology. So now we present to you tech Stuff, Adjust the thermostat. We're going to take the temperature today in our podcast. Yeah, we're gonna talk about the thermostat. Now, we've already talked about air conditioning we have on the show, so but we didn't didn't cover thermostats at all when we talked about air conditioning, not really. And the thermost that, of course, is that handy dandy little device that helps you maintain

the right temperature. Because you know, there are air conditioner and heater or units out there that don't use thermostats. You manually have to turn it on or turn it off. So when you're like thinking galy g the house shore is cold. Now I don't need that air conditioner on anymore. You can go and switch it off. But most of them tend to have some sort of thermostat in there

which helps maintain a comfortable temperature. You set the temperature you want, it starts whatever the process is that needs to get to that temperature, whether that's cooling the air down or heating it up, and then once it reaches that temperature, ideally it shuts off so that you don't continue on the pathway to reach the other side of uncomfortable. Well yeah, and uh it's also I think the second largest lead leading cause of divorce. I wanted their degrees colder.

Are you done? Okay? Yeah? No. Uh. Thermostats are not not exclusive to houses, of course, or or buildings or or keeping people comfortable. They're also in many other devices for keeping those devices comfortable, like say a car for instance, um anything that that where you need to measure temperature and switch on a cooling or a heating um in your In your car, it might turn on the cooling fan when it senses the engine might be nearing overheating um.

And if you look at a house thermostat. And you see one of those digital, high tech programmable models on the wall, you might get the idea that they are super duper sophisticated. But thermostats don't have to be that sophisticated, and in fact actually use physics to um determine or you know, just set off the switch inside that makes things hotter or cooler. Yeah, it's actually pretty cool in a way. You know, I don't mean that in a temperature way, but I see what you did there. These

things are hot. Uh. Now, they, like Chris was saying, yeah, uses physics. If you're looking at Let's say, let's talk

about one of the old thermostats. Okay, So so it's like that little beige box that's sitting on the wall, and it's got a little up got a dial, yeah, either a dial or a lever, and it has a little physical read out that you look at, and it's got a little red needle in that that read out, and by turning the dial or moving the lever to the left or to the right, you move the needle up and down this temperature range to set it to

whatever you want. So let's say we're gonna say that the temperature inside the house right now is a is a chilly sixty five because because we're in the dead of winter in Georgia and so so we want to we want to boost that up to about seventy two.

Let's say we want we wanted to be a little warmer, maybe a little warmer than we normally would, because it's kind of chilly, and we want to I want to have a nice little day and side, so we moved the the lever so that it moves up to seventy two and then magically the heater comes on until it hits around seventy two degrees and then shuts off. But what's going on inside, well, inside the thermostat is at

the very heart of it is a mercury switch. Mercury. Yeah, don't drink it, no, No, mercury is pretty cool stuff. It's uh, you know, it's a it's a metal which at room temperature is liquid. Yea. As a matter of fact, my family, for some reason, when they broke an old mercury thermometer, decided to keep the mercury in a baby food jar, which oddly enough, we still have. Of course, it's sealed up, you know, touch mercury is highly toxic. Yes, yes, you do not want to have any contact with mercury.

But um mad as a header. But sealing it up inside a jar, you know, I got to see, you know, move it, and it's it's really neat to watch it break apart into little metal falls and then reform. Yeah, it's like, yes, exactly, it's the one when the t in the documentary Terminator Too would come apart. You know, you would see it kind of turn these liquid shapes and then reform. Well that's essentially, you know, that's mercury.

That's what mercury does. Although mercury rarely will take essentience and then chase after Sarah Connor, that part, Yeah, that part doesn't happen that frequently. Um. But but it is a liquid metal. And uh, and here's the thing about it. Here's where we get into some physics. We're gonna you know, we'll get into more in a little bit, but metals um actually pretty much everything will tend to expand when

exposed to heat. Now, what's really happening is that you're adding energy into a system and the atoms in that system start to move around. And this is what in effect causes expansion. And of course if you add enough heat to something, depending on what it is, not everything will well they urize, but a lot of stuff vaporizes will turn into a gas form. Uh. That's really when the atoms are have so much energy and they're moving around so much, they're no longer cohesive as a liquid um.

So mercury, it takes a lot of It takes way more heat than it would then we would generate to turn mercury into a gas. But all right, in its liquid form, what happens is you put it into an enclosed space, you add heat, it's going to the liquid inside that enclosed space is going to expand. The volume increases as the temperature increases. So if you were to put mercury, say in a glass bulb, that one side

is elongated into a tube, very thin tube. As the heat increases, the mercury would appear to climb that tube. It's because the mercury itself is expanding, the volumes increasing as the temperature increases. And that's the basis of a thermometer. The old mercury thermometers, you would have this class to tube that was filled with mercury. You would have numbers that would correspond to whatever the temperature was, and then as the temperature rises, you'd see the little level of

mercury increase inside that glass tube. You know, suddenly I want to ride my bicycle. That's a different kind of mercury. You want to ride your bike? Yes, that would be nice, fat bottom girls, you make the rock and wood, alright, alright, the same song does reference it anyway, that's true. That's true. So and a thermometer that you've got the mercury expanding to tell you what temperature it is. Yes, but there's a mercury switch, as you said, inside the thermostat right now.

In this case, the mercury switch is it's a little different. It's not it's not acting as a thermometer. It's a glass vial and it has three wires in it. There's a wire that goes along the bottom of the glass vial, which is in constant contact with the liquid mercury, and then you have wires on the left and right side of the vial that are just out of contact with

the mercury. But the vial itself can tilt to the left or to the right, and when it does tilt, the mercury then comes in contact with the wire that's on that particular side of the glass vial and then completes a circuit between the bottom wire and the wire that's on the respective side. So let's arguably say the the vial tilts to the left, the mercury now is in contact with both the wire along the bottom of the vial and on the left side of the VISal,

and now you've got a circuit. So this gives us some opportunities here if we create a system that will tilt the vial one way or the other based upon certain parameters we haven't. We have a switch, and we have a switch that can either be off or it can be on on two different directions, which is great for heating and cooling. Yes, so now we think, okay, well, you've got the switch. Uh let's say that you you want to adjust the heat and you want to turn up the heat, and you you move that that uh,

that lever over that's going to tilt that glass vial. Right. The mercury is gonna move over to the correct side, and that's going to initiate it's going to complete a circuit and then send electricity to the heater, which will get the heater going and the fan will start to turn and you'll start to have warm air pumped throughout the house or whatever it is that you're in. Right, Okay, So how does the thermostat know when to stop? Well, more physics. Now, you know we've we've talked about how

mercury is used in thermometers. And you might say, oh, so it's sort of acting like a thermometer, right, because it can tell if it's hot or cold. No, in this case, mercury is just acting as a conductor. And because it's it's useful because it's liquid in this case, and it will make it will flash into the and and touch the two contacts together in the appropriate case get a little steamy. In this podcast, I think we need to take a quick break to thank our sponsor.

Using a thermometer called bimetallic thermometer, and based on its name, you may be able to discern what's special about this kind of thermometer. Yes, it's got to to two metals and one actually it's not in one. They're laminated together, yes, to make a strip. So so yeah, on on one side of the strip you have one metal and on the other side of the strip is another metal. They're

joined together. And here's why you want this. You see, different metals will expand at different rates in in reaction to a change in temperature. So one metal, when you when you apply heat to it, might expand rather rapidly, while a second medal, in relation to the first one, will go more slowly. And you put these two different pieces of metal together, and as one expands an at a rate that's faster than the other, it's going to

change the shape of that sheet of metal. Now, in the case of these thermostats, these bimetallic thermometers tend to be arranged in a coil, and so you've got a coil of this material where on the outer edge and the inner edge it's two different metals. The inner edge is usually the one that expands faster um when when heat is applied. You've got it in this coiled shape.

And uh, the way this works is that when it when the temperature rises, the the expansion on the inner layer of this coil will cause the coil to uncoil, start to unwind. When it unwinds enough, it actually presses up against the mercury switch and puts it back into its central configuration. Okay, I don't need to be on anymore. I'll turn off exactly. The mercury no longer is in contact with both wires, because once it is set back to its central location, only the bottom wire is connected,

the circuit is broken and the heater stops working. Uh. And in general, usually there's a system in place where this will actually shut off before you reach that full temperature, because depending on where you are in the house, like you don't want the thermostat to be right next to the heating vent no, because it'll the temperature of the thermostat will change too quickly, right, so you would you might be in a situation where if the hot air

were right next to the thermostat, the thermostatic goes, oh, okay, it's already seventy two degrees. Meanwhile you're in the living room going why is it so cold in here? Right?

So you want the thermostat to be someplace where it will be exposed to the flow of air, but won't be right there at e vent So the thinking here is that, well, if we we may want the thermostat to shut off a couple of degrees cooler than what you said, it at because the room that's going to be closer to the actual event is going to be warmer than where over the thermostat is, and the heat

will disperse throughout the house. So it's kind of a way of making sure you don't get too warm, because then you're gonna be saying, they're thinking, I said it to seventy two, and now it feels like it's like seventy six. What's going on? So um to do that, they have a resistor inside the thermostat, No, I'm not

going so. Resistors will actually heat up as electricity goes through them, and the resistor itself acts as a heater for that coil that's inside the thermostat, so it will expand a little faster than it would if it were just measuring the ambient temperature of the air. Right, so uh, that will cause the heater to to shut down a little more quickly than it would if if it were

just reacting to the ambient air temperature. So um, of course, if the house cools down, you know, after you've heated it up, then that coil is going to slowly start to contract, you know as as it's uh uh, as that temperature drops and if it contracts enough, then the mercury vial is going to tilt again, and that's going to start the system all over again. You get that completed circuit, sends the electricity to the heater, and you

start up again. The same thing is true by the way of air conditioning, except you know, you're talking about contracting instead of expanding. That's the it's just tilting the mercury vile the other way, and as the temperature goes down, the coil contracts, and then the vial will eventually be set back to its central configuration. Uh. Now that this is your basic analog thermostat. That it's not the way all thermostats work. It's the way the older ones work.

So if you ever in a building that has that and you hear that clicking noise, that's the sound of the vile actually turning and uh and and the circuit completing. Um, that's that's what you're hearing there. Some thermostats are using thermistors, which are sort of digital thermometers. It's a little different. That's that's not UM based on the mercury switch necessarily, although some are kind of a hybrid between the two. Yeah, I actually think that that that system is brilliant because

it's relying on the laws of physics. You know what, you're not going to change for the thermostat, So it's not like neutrinos are suddenly going to go faster than the speed of light. Right, um. And that was a joke, people, I know, I'm reading up on the whole story. That was just a me playing playing a joke about the

laws of physics not changing. Right. No, But it's a it's a brilliant system because it's so simple and it's design um and very frankly, I've I've found that the manual thermostats, while they don't necessarily save you as much energy as a programmable uh, some programmable thermostats are real painting the neck to you, especially if you don't realize what what setting it's on, or you take a week of vacation and you're at home and you're thinking it's so warm, and oh it's on the programmed one as

opposed to a constant I almost always turned the program off, which is not terribly um efficient and and actually one could argue irresponsible of me because it means I'm wasting electricity and uh uh, that's probably no, that's I can't really argue with that, right. Well, um, well, the digital ones that use the thermistors. In case you're wondering how the thermistor works, it actually is um allowing uh. It changes the electrical resistance of the material inside as the

temperature changes. That's how it determines, uh, if it's at the right temperature or not, or whether you know, the

the heating or cooling device needs to be still going. Um. And of course the programmable thermostat still use still need to be able to identify what temperature it is because um, you know, it's it's simply adding a layer of electronics to the simplicity of the thermostat, because you know, you're just saying, okay, at six in the morning, I wanted at this temperature at you know, two in the afternoon, and I wanted at this temperature on the weekend, I

wanted to be this. You know, Once you do that and it has uh the clock in it internally set correctly, assuming that your batteries don't die. Um, you know, it's it's just adding a layer of complexity. But the thermostat at its heart it's still using uh you know, basically measuring the temperature and using the switch to turn the heat or cooling system on or off. Yeah. Yeah, so yeah, there's certain components that are gonna be uh common across

all thermostats. They may not take the exact same form, but they follow the same function. Yeah, even in a system where you have zoning. Yeah, zoning can be important if you're in a well, if you're in the build office built in an office building, clearly you're gonna need zones because the especially if it's say it's a high rise um or a skyscraper, that's the temperature is going to vary quite a bit from the very top to

the very bottom. Especially if you imagine that there was no heating or cooling system in there at all, you would know, you know, well, it's gonna feel a lot different on floor number one than it is on floor number fifty. So so you've gotta have special zoning in there. But even some houses will have it, especially depending on

the the layout of the house. You know, some houses are if they're like a flat style where it's it's multiple floors, it may be that the the bottom floor is always much cooler than the top floor, and you might want special zoning there so that the entire domicile remains and a comfortable temperature. Um. So yeah, I mean

that's also fairly common. And we're also seeing some web connected thermostats these days where you can even you know, manage your home's climate remotely the Internet of Things, Yeah, which is interesting and frustrating in the sense that it's frustrating in the sense that there's not really a standard way to approach this yet. So it's all proprietary. Yeah,

but you can, you can. There's several different companies that offer home automation systems and basically what you do is you set the UH different systems up and we're talking things like locking and unlocking the doors, turning lights off and on, um, the thermostat, and all sorts of other things, perhaps UM camera security system some you know, the different things, and you can have the system set up to where you can manage all these things through a computer or

even your smartphone now um. And yeah, I mean it's it's it's pretty simple. It's just uh, you're right. I mean a lot of the times the hardware UH is proprietary. So let's say you have one company and their billing has gotten out of control, and I could I could get a cheaper system. Um, you're likely to have to have the new company come in and install their equipment, because it won't they can't go, oh, well, you know, I can, I can use so and So's equipment. You're

probably not. Now that's not necessarily true, but it is in in some cases. There's also the possibility. There's also the possibility that whatever company you go with ends up going out of business. And if that happens, if your commands are sent through corporate servers before they get to your house to make whatever the changes are, if that company goes out of business, then you're out of luck. I mean, most of these systems still have the way you know, you can still program it manually, so that

it's not like all functionality is gonna disappear. It's just that the extra stuff you pay for might not stick around. But that does bring us to an interesting development, something that has made the news recently. Uh, and it's it's kind of interesting that that's such a you would normally think thermostats those are fairly mundane. Yeah, I mean the sort of thing that usually makes waves in the tech world.

I could guarantee you that that the thermostat you were describing earlier in the episode is something that just about everybody we're talking to on this podcast has seen in somebody's house at some point. Yeah, simply because um it's so reliable. Thermostats don't just break in a lot of instances. So I've seen, you know, the old mechanical thermostats last years and years and years and years. Um so, and I could just about guarantee that people have seen the

type that you were talking about before, the pre digital variety. Okay, now I've been chilling out to this podcast tool and now it's too cold in here, all right, I gotta make another adjustment. In the meantime, let's take a quick break to thank our sponsor. So, you know, other than the programmable thermostat, there hasn't been I would say, a massive surge in thermostat technology. Yeah, the web connection is

probably the closest thing that we can come to. But even then you're just adding some sort of connectivity to the device. In this case, we're talking about something that that goes a step beyond just connectivity. And we owe thanks to Mr Tony Fidel, who made a real name for him self developing being one of the developers on a truly iconic product, which is the iPod. And in fact,

it's so iconic that we have podcasting. Uh. And yeah, there are people who refer to it as netcasting or or webcasting, but but truth you know, the podcasting is like the common that's different. Podcasting is is the common term for what what it is that Chris and I are doing right now. Um, and we you know, it

owes everything to the Apple iPod. It was the MP three player that it was not the first MP three player to hit the market, but it was a huge success and it essentially defined in the market once once the iPod hit and people started to adopt it, all other MP three players at that point for moving forward

were essentially guided by the iPod. Either they were trying to do what the iPod did but do it better, or to try and completely depart from the way the iPod did things in a way to differentiate the the product from the standard bearer. Really so well, I was gonna say one of the things that made the iPod great and it's time was the simplicity of its controls.

And you'll remember, just a couple of minutes ago, I was talking about how some digital thermostats can be a real pain in the neck to use UM because the controls aren't necessarily UM aren't necessarily straightforward in their labeling. Yeah, or it may it may take multiple steps just for

you to go. Like if you want to get really granular with your programming, so that you know, for instance, uh, you might tell a work one day out of the week, and so you want that one day out of the week to have a slightly different program than all the other work days that you have. You know, so let's say that you let's say you work from home on Tuesdays, and so, uh, you know, Monday, Wednesday, Thursday, and Friday you want to set up so that's going to save

as much electricity as possible while you're away. But on Tuesday's you're going to be home. So you're gotta make sure that when you program your your thermostat that the Tuesday is the exception and your weekends are exceptions because you know your weekend you're not gonna be away from your home the way you are during the work week. So getting this program in a typical digital thermostat can sometimes be frustrating. It's like setting an old VCR you're

put kids, ask your parents what VCRs were. But Monday, Tuesday, right, okay, Wednesday two pm, three pm too late, gott to go around the horn. Yeah so yeah, back, it could be a little bit of a frustration, a little bit of an exercise and frustration. So the Mr Fidel, who now works for a company called Nest Labs, decided to try and develop a thermostat that would be easy to program, and not just easy to program, but could learn how to program your climate control system in your home based

upon your activities. Yeah. Yeah, now, I mean Nest Labs is a fairly new company. Um uh Matt Rodgers, who worked on the the iPod and iPad, was the co founder and vice president of engineering for Nest Labs. Um and he uh. He interviewed with uh Martin Lamonica at uh C net, which was an interesting interview. I'm just talking about how the point is to make a very simple and easy to use thermostat that picks up, uh,

picks up what you're trying to lay down. Man. Yeah, it's it's paying attention to the way you like things. It's called the the it's the Nest thermostat, the and the nest learning thermostat in fact, uh so uh very simple looking designs, a little round thermostat has has the

temperature and nice big digits so it's easy to need. UM. It even has a little leaf icon that will pop up whenever you're using the thermostat to its to its best efficiency, so that you're saving power and you're conserving electricity. We've seen that actually in other products as well, particularly in cars. Cars that are supposed to be energy efficient, now many of them, Yeah they have a little leaf icon,

the Nissan Leaf being the leading example. But yeah, seeing this pop up in other products now and in this case, yeah, it has this feature where not to you have the remote control that you have with other web enabled thermostats, but in this case it actually starts to um follow what you do and it will start to proactively make adjustments based upon what you have done in the past, and it will even do things like connect to the

web and look at things like weather reports. So you know you've set up the system, you have a web enabled to some it knows where you are based upon the information you've put in. It's not like there's a GPS or anything in it. It's that you are entering this information. So in our case, we'd say Atlanta, Georgia.

And then because it knows we're in Atlanta, Georgia, let's say there's a heat wave that's moving through Atlanta, Georgia, it already knows proactively that the temperature outside is going to to go up, and it starts to prepare everything so that the air conditioning system is going to be more active during those times than it would be if

the temperature were, you know, more moderate. So it's kind of interesting in that it's not just learning how you work, Like maybe it learns, you know what, he likes it pretty cool at night, but by the time it starts getting to the morning and wants a little bit warmer, it starts to make those adjustments based upon how you adjust the thermostat yourself. Um, it also will anticipate your needs based upon what's going on outside. It's pretty cool.

It is very cool. It is also very pricey. It's around two and fifty dollars, and here here in the United States, that's quite a bit more than most programmable thermostats i've seen. That being said, two fifty dollars when you look at personal electronics is really reasonable. I mean, like, like I'm looking, I'm I'm When I heard two hundred

fifty dollars, my reaction was wow, that's all. But that was because I was thinking about the smart technology and the programmability and and how it does this anticipation, and how much money it would, at least in theory or could save you. Because that's the big thing is that up to fifty of the typical American electric bill goes to heating and cooling, So if you were to improve efficiencies,

you could theoretically save money. In fact, there are some estimates I saw where you could save up to a thousand dollars a year with the right system in place, which means that in a quarter of a year you've already paid off the purchase price of the Nest. Yeah. That being said, Nest is not sponsoring this podcast. This isn't an advertisement for Nest. It just was one of the points that they brought up, at least in their

marketing speak. Yeah, and and it's important to note too that this system isn't so firmly ingrained in another system to the point where it can't be used as a standalone device. As a matter of fact, that it's uh um even though the creators are are formal former appollites. UM. The Nest can be used with an iOS device or an Android device so that you can actually uh make contact with it and change the temperature if you need to UM. And it uses WiFi on its own, so UM.

You know, it doesn't have to be hooked into some brain somewhere else in the building as as some other systems. And I want to point out to it's not all home automation technology that requires those systems, but some of them do. UM. So there are some that just hook up directly to your home network, and this is one

of those examples. This links directly into your home wireless network. Earlier, I was thinking of the home automation system that is offered through my alarm company, and if I wanted just a centralized operating so yeah, exactly, and if I wanted to take advantage of that uh and and later on switch providers, they would end up not being able to use that equipment. But yeah, there there's other stuff you

can use now. According to Nest Labs, it takes about a week for this thermostat to learn what you like based upon you know what what you tell it during during that first week, which is kind of interesting to me too, that the algorithms are so so um sophisticated that you can pick up on your activities that quickly. Um raisins he likes. It makes me wanna. It makes me think that there's gotta be ways where you can

screw with it. Like I would just imagine going to someone's house who has this and just like they're just gonna think that he wanted at ninety two degrees at three in the morning. Well, and and yesterday, um, literally yesterday for then they were recording this. Uh, the uh maintenance guy came to do our semi annual uh check up on my furnace and you know, does the heating

and air conditioning thing. And of course to do that they have to crank up the thermostat to something that's ridiculously higher to make sure the heat or the air conditioning comes on so they can check it. And so I wonder what the nest would do. It's like, wait a minute, why does he suddenly wanted at eighty five degrees? Uh, that's kind of strange anyway, Uh, it's interesting to see that they're just it's interesting interesting to see some some

real development in this field. When you know, when you consider that again, like Chris was saying, this is not exactly one of those technologies that has had you know, a meteoric rise in sophistication over the last several decades, and for the for many years, it just kind of the old the old analog systems were that was that was what you saw. Yeah, but you know, they're all still based on the same principle of trying to to get the climate at the right perture and then maintaining

that until you change the settings. So some thing's never change. By the way, if you are interested in reading more about the thermostats and exactly how these these systems work and things like the bimetallic thermometers, um, we have some articles on how stuff works that cover this, including how home thermostats work, which is a very comprehensive article about

the whole system. And then we have how thermometers work, which was written by our very own martial brain uh that will go on into more detail about things like the bimetallic thermometers if you want, if you're interested and want to learn more about that, you want to get deeper into the physics of it. I recommend both of those, alright, guys. That wraps up this classic episode of tech Stuff where

we talked about thermostats. It was always enjoyed to revisit those episodes I recorded with Chris Palette so long ago. Hope you guys enjoyed it as well. If you want to learn more about the show, including ways to contact us, hey it on over to tech Stuff podcast dot com. That there's all the information right over there, and go to t public dot com slash tech stuff to visit our merchandise store. That's where you're going to find all the cool tech stuff stuff like tope bags and T

shirts and stickers, things like that. Check that out and I'll talk to you again really soon for more on this and thousands of other topics because it how stuff works dot com