Making a Learning Thermostat

OzPeter writes "As reported in WA Today, Tony Fadell of iPod fame has been using Nest Labs to design and build a thermostat that learns how you live in your house by following how you manually change the temperature. Once you have taught it how to behave, it then can schedule temperature changes that suit your lifestyle, and help you cut down on energy costs."

Comments

Women

[Dan East]

Don't let women use this thing. It will only learn two settings: the maximum temperature setting and the lowest temperature setting. At least that's how the females in my life use them.

Re:Women

[cvtan]

This is absolutely true. Apparently heating systems (even totally automated ones with thermostats) have only two settings: on and off. If you want the temp to be 72, you set it to 85 so it heats up "faster", then when it's too hot, you turn it off. The temperature is always wrong so you have to keep adjusting. It makes you feel needed.

Re:Women

[ooloogi]

For some reason people tend to assume a proportional controller, and want to help it out doing its job.

Re:Women

[rtb61]

Air-conditioning is completely different. It will only reduce the temperature of the air over the indoor coil by the capacity of it's compressor, the size of the evaporator and condenser coils and outside temperature. The amount of cooling achieved and how long it takes, depends upon internal heat loads, insulation values and volume of air to be treated.

Whether it's a dial or digital read out, the result is the same. Getting to your desired temperature will not be achieved faster by turning the dial or setting the thermostat beyond desired temperature. In most circumstances it will never be achieved simply because the unit is undersized for the load required. Instead of dicking around with thermostats, I can give you a big hint, the efficiency of air conditioners is driven by the size of the indoor and outdoor heat exchangers, by making them small the manufacturers, the lying scum sucking pigs, cut costs and advertise compressor horse power and you lose big time. Always do a comparison of actual cooling energy output and electrical current used to achieve it. Big efficient heat exchangers and a lot of cost to the unit, as well as things like type of electric motor and type of compressor.

Even things like the location of the thermostat have a big impact on how effective your air-conditioning feels.

Learned Stupidity

[LunaticTippy]

Most thermostats will learn stupid conflicted behavior. Cold person irrationally turns thermostat up to 80. Angry frugal person retaliates by turning down to 50. Repeat 20x/day. Leave it alone at random during nice weather.

I like thermostats that are more even-tempered. My programmable one has a nice feature that if overridden will resume at the next programmed temperature interval, so someone cranking the heat or AC will only be able to influence the next few hours at most.

Re:Learned Stupidity

[Dan East]

Hmm, I have an idea. A truly smart thermostat would lie. It would indicate it's set at some crazy temperature, but in reality it would apply a moderate setting. Or better yet, it would lie to everyone but me.

Re:Learned Stupidity

[BasilBrush]

Cold person irrationally turns thermostat up to 80. Angry frugal person retaliates by turning down to 50. Repeat 20x/day.

Ah, but the thermostat also has the information of what the temperature actually is when they turn the dial.
Cold person turns it up at temp X, frugal person turns it down at temp Y.
X is too cold, Y is too warm. Good compromise temperature is between X and Y.
80 & 50 are irrelevant.

The whole point of this rethink is to look at heuristics like that. Not just to learn, but to be intelligent about it.

Re:Learned Stupidity

[kd5zex]

I just filed for a patent on this, thanks!

Re:Learned Stupidity

[NEDHead]

It is a well documented fact that in some office environments, fake thermostats that the workers can access improves perceived comfort and reduces calls to maintenance.

Overly complicated

[hawguy]

Sounds overly complicated. With my current thermostat, I set it to make the temperature to 70 degrees at 6:55am (just before my alarm goes off). It learns how fast the house heats up, so the house really is at the right temperature when I want it to be and it does a pretty good job of that, even on unusually cold days.

If I have to manually adjust the temperature to help it learn, then it's going to lag my preferred time by 5 or 10 minutes (the time it takes me to get out of bed and go down to the thermostat and reset it). Or does it learn how long it takes me to get dressed and walk from the bedroom to the thermostat? And if it uses motion sensors to decide whether or not I'm home, it's either going to think I'm never home since I don't go past the thermostat much in my day-to-day activities, or it's going to think I'm always home when it senses the dog going to her food dish.

I'd much rather have a thermostat with an easy to use UI than something that tries to be smart. Maybe if I had a true smart-home with sensors in every room, it could automatically figure out what time I wake up and when I leave the house, but I don't see how a thermostat on a wall can do a good job.

Re:Overly complicated

[JBMcB]

I don't know if you saw the nest - but it's just a knob. You turn it until it's at the temperature you want. That's it. No fan control, no heat/cool setting. It just makes it the temperature you want. Then, as you turn it up and down, it learns *when* you want it to be a certain temperature. It also checks via wifi what the temperature outside is, so it learns the delta between preferred indoor and outdoor temperatures (we keep our thermostat at 68, but if it's 65 and sunny outside we turn the furnace off)

It seems pretty nifty, if for no other reason you can set it via the web if you aren't coming home as scheduled.

Re:Overly complicated

[BasilBrush]

Or does it learn how long it takes me to get dressed and walk from the bedroom to the thermostat?

If it's occurred to you in the few minutes between learning about the device and posting here, why would you imagine that it hasn't occurred to them? There's no reason why it can't work out which is the morning increase, and assume that in future you want that temperature 10 minutes earlier in the day, or 5, or 20, depending on what their research in the field has found to be satisfactory for most people.

And if it uses motion sensors to decide whether or not I'm home, it's either going to think I'm never home since I don't go past the thermostat much in my day-to-day activities, or it's going to think I'm always home when it senses the dog going to her food dish.

They say the best place for thermostat is in a hallway. People should be passing that from time to time. But they do say to turn it down yourself hen leaving and up when you return, at least for the first week, to give it a good start on working out your patterns.

And placed at the normal thermostat height, the detector isn't set off by dogs. That's a FAQ.

I'd much rather have a thermostat with an easy to use UI than something that tries to be smart.

I've never seen an easier UI than this one. There's only one control and that's a temperature dial. Personally I'd far prefer one that's smart.

I don't see how a thermostat on a wall can do a good job.

Ah well, if you can't see it, then obviously it doesn't work.

"No wireless. Less space than a nomad. Lame."

Re:Assuming

[BasilBrush]

No it doesn't. In fact right at the start of the animation you see what are obviously different people's hands adjusting it.
Existing programmable thermostats assume one person in control. Or at least solely cater for the last person to alter it. Nest appears to be more democratic.
Whether that's a good thing or a bad thing depends on your household!

Simple, 55*

[DigiTechGuy]

55* is enough to keep the pipes from freezing. I don't have the money to justify a cozy 68*-72*. Want it warmer? That's why they make clothes and blankets.

Re:Simple, 55*

[adolf]

Meh. 33 is enough to keeps the pipes warm. And if you're really being frugal with the layered clothing/blankets thing, it's often cheaper to set the taps to "slow drip" than it is to set the thermostat to "substantially warmer than freezing."

Or just wrap heat tape on the pipes, and turn the furnace off. The water will still flow, the house will still be predictably fucking cold, and you'll still be able to bask in your frugality.

Re:Simple

[ooloogi]

We ended up just opening up the windows to let the house warm up to a nice temperature. It's such a waste that the air conditioner keeps trying to cool the whole city to 20C, but dad pays the bills so that's his problem.

-- The Girls.

Well it turns out those actually DO exist

[Sycraft-fu]

Really, I was surprised, but I have one on my A/C. So my A/C is a dual stage unit. Basically it has a bypass so that when it doesn't need to put out so much cooling, it can work the compressor less, spin down the fans, and so on. When needed, it can use full capacity. It is a 4 ton unit that effectively has about a 2.5 ton mode. Good for saving energy. Most days all you need is the first stage, even in the desert.

Well the thing is, the stage use is determined by two degree bands, temperature deltas. The first you set between 1 and 6 degrees. This is how much the temperature can swing before the unit engages. So if the degree band is 3 and the thermostat is 75, the A/C will come on at 78 (or the heat at 72 if in heat mode). The second one is another two degrees fixed. When the temperature is more than the first band plus the second, the thermostat engages the second stage of the A/C. So if set at 75 with a 3 degree band, the second stage engages at 80 degrees.

Needless to say the thing cools a hell of a lot more when fully spun up. So you really can make it cool down faster by setting the temperature lower.

In fact, I have to when it is really hot. When it is very hot, like 105 or above out, the low stage is really only enough to maintain the temperature. It cools as fast as heat leaks in (that is the design idea more or less). So to actually get it to cool, I have to kick in the 2nd stage. Means if I want 75, I set the temperature lower, until it hits 75, then set it to 74 and the A/C will continually run until the outdoor temperature cools off enough.

And yes, it is more efficient to run continuously in the low stage than cycle on and off in the high stage.