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Anyone have Nest Thermostat

Tomorrow

Tomorrow

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Mar 2, 2008
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HE15MAN said:
Where do you live? 85 is nasty hot and would take at least 35 minutes to cool off down here.
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Near Dallas. Since the thermostat is programmed, it turns on before we get home - so it's nice and cool when we do.

Also, just because the thermostat is set to 85 doesn't mean it's actually that warm in the house - it seldom gets that hot, except for upstairs. The thermostat uses the current temperature, the current time, and the anticipated program to turn on in time to get the house cooled off.
 
falstaffpac

falstaffpac

macrumors member
Jun 23, 2010
48
1
St. Louis, MO
I learned of this thermostat about 3 days ago and have been obsessing over it (not something I typically do). Purchased it this afternoon and installed it. Geek factor is 10/10. The last thing I typically think about is our home thermostat. My wife and daughter determine our house temperature, for the most part.

The device is elegant, well packaged, and the company provides very good online technical support. I really like the idea of the little leaf lighting up when you conserve energy (I'm delusional and think my wife and daughter will become more energy conscious if they see the leaf).

The device connects to the internet, and requests your zipcode. It then is able to determine relative outside temp to inside temp and determine the effiency of your system relative to your house.

The purchase was a little hard to justify, as compared to my digital/programmable thermostat I picked up at Lowes about 10 years ago for $20. I think its pretty cool though, I'm happy with it.
 
HE15MAN

HE15MAN

macrumors 6502a
Original poster
Sep 3, 2009
955
14
Florida's Treasure Coast
falstaffpac said:
I learned of this thermostat about 3 days ago and have been obsessing over it (not something I typically do). Purchased it this afternoon and installed it. Geek factor is 10/10. The last thing I typically think about is our home thermostat. My wife and daughter determine our house temperature, for the most part.

The device is elegant, well packaged, and the company provides very good online technical support. I really like the idea of the little leaf lighting up when you conserve energy (I'm delusional and think my wife and daughter will become more energy conscious if they see the leaf).

The device connects to the internet, and requests your zipcode. It then is able to determine relative outside temp to inside temp and determine the effiency of your system relative to your house.

The purchase was a little hard to justify, as compared to my digital/programmable thermostat I picked up at Lowes about 10 years ago for $20. I think its pretty cool though, I'm happy with it.
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I was oddly the same way, but learned of it around a month ago when the Verge did an article about the new software update Nest pushed out with AirWave and a few other things. I have thought about buying one everyday since then. I now see Apple stores are going to sell them as well
 
mscriv

mscriv

macrumors 601
Aug 14, 2008
4,923
602
Dallas, Texas
Tomorrow said:
When we moved into our house, I replaced our thermostats with programmable ones. I set them to raise the temperature to 85 degrees in summer when we aren't home, and programmed it for us to be "not home" during our work hours and all day on weekends. It's a simple matter to override this if you're actually home when it thinks you're not, but we're almost never gone when it's programmed for us to be home - so it's never trying to keep the house at 76 when we're gone. Not quite as savvy as a stat with an occupancy sensor, but every bit as effective.
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Hey Tomorrow, I've always heard that doing this kind of thing doesn't really save you any energy because your system has to work harder to move temps up and down such large gaps (10 degrees or so) as opposed to just maintaining a set temp all day long. I know you've worked in AC and cooling so I guess what I've heard is just "rumor". What say you my expert friend?
 
Tomorrow

Tomorrow

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mscriv said:
Hey Tomorrow, I've always heard that doing this kind of thing doesn't really save you any energy because your system has to work harder to move temps up and down such large gaps (10 degrees or so) as opposed to just maintaining a set temp all day long. I know you've worked in AC and cooling so I guess what I've heard is just "rumor". What say you my expert friend?
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A home A/C unit is either "on" or "off" - there is no such thing as "working harder," only "working longer."

That being said, if you're able to turn it off for nine or ten hours (either manually or with a programmable stat) and it only takes half an hour or less to recover, then you've just saved a bunch of money. If your equipment is undersized for the house, or very old, it might struggle on very hot days - in those cases, your recovery time could well be two or three hours. It would still save you money, but you'd be sitting in a sweltering house until it finally cooled down - not worth it, IMO.

In a variable system - such as in an office building - there is such a thing as running at part load vs. full load. In this case, turning the equipment off when the building isn't in use is still a money saver, but it might be on the order of 20-30% instead of 40-50%. You may have noticed that building managers often turn the A/C off overnight and on weekends; that's why.
 
Weaselboy

Weaselboy

Moderator
Staff member
Jan 23, 2005
34,136
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California
Tomorrow said:
A home A/C unit is either "on" or "off" - there is no such thing as "working harder," only "working longer."
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Not necessarily. My home system has a two speed compressor outside and a variable speed fan inside, so under low loads (once the house is cooled down) the compressor and cooling fan outside go to low speed as well as the ventilation fan inside dropping to a very low speed and efficiency is increased significantly.

So if I turn up the AC to 85 and have it drop back to say 78 an hour before I get home, in my case everything (compressor and both fans) WILL be operating at high speed (working harder) and less efficiently to pull the temp back down from 85. This really eats into any saving from the setback temps.

There are studies with results in both directions on this. It really varies a lot depending on the AC system and outdoor temps as well as how tight the house is. With the right system that includes a two speed compressor and variable speed fans the difference using "setback" temps can be close to nothing.
 
Tomorrow

Tomorrow

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Weaselboy said:
Not necessarily. My home system has a two speed compressor outside and a variable speed fan inside, so under low loads (once the house is cooled down) the compressor and cooling fan outside go to low speed as well as the ventilation fan inside dropping to a very low speed and efficiency is increased significantly.
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This is indeed an unusual system for a residence.

So if I turn up the AC to 85 and have it drop back to say 78 an hour before I get home, in my case everything (compressor and both fans) WILL be operating at high speed (working harder) and less efficiently to pull the temp back down from 85. This really eats into any saving from the setback temps.
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Yes, it will be less efficient - for no more than an hour. There's still a lot of energy saved overall, if you're gone 9-10 hours (a typical workday).

There are studies with results in both directions on this. It really varies a lot depending on the AC system and outdoor temps as well as how tight the house is. With the right system that includes a two speed compressor and variable speed fans the difference using "setback" temps can be close to nothing.
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I've done many of those studies (it's my job). I'll agree that using a variable speed or two-speed system is more energy efficient at part loads, but it's still using energy vs. a system that's turned off completely. Remember, the system in recovery mode will be running at 100% whether it's a single-speed unit or a variable-speed unit. Recovery time is typically under 30 minutes (it's around 15 minutes at my house, but I have two A/C units). Even at an hour, you're still using more energy running all day at part load than you are by turning it off, or to a proper setback temperature.

Check ASHRAE standard 90.1. There's decades of research in there, and I've written dozens of reports for clients on this very issue.
 
Weaselboy

Weaselboy

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Staff member
Jan 23, 2005
34,136
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California
Tomorrow said:
This is indeed an unusual system for a residence.

Yes, it will be less efficient - for no more than an hour. There's still a lot of energy saved overall, if you're gone 9-10 hours (a typical workday).
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My system is not unusual at all. Go to any brand AC system web site and the first two or three systems listed are all two speed compressors with variable speed furnaces. I am very familiar with what is being installed in my area and almost everybody but the extremely budget constrained are using a system like mine. To get the better rebates it is a requirement.

I don't know where you live, but there is no way a properly sized unit where I live (very hot climate) would pull down from 85 to 78 in an hour.

I'm not going to back and forth with you all day on this. My point is it is not so clear cut that setback results in huge savings, and depending on the system the savings can be zero or very small.
 
A

aristobrat

macrumors G5
Oct 14, 2005
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Weaselboy said:
Not necessarily. My home system has a two speed compressor outside and a variable speed fan inside.
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Same here. In my area, that was somewhat of a "higher-end" thing when I had my system redone about 5 years ago, but it now seems to be the default for everything going in around here.

Unless Nest has recently updated their product, it doesn't support multi-stage compressors though. :(
 
PinkyMacGodess

PinkyMacGodess

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Mar 7, 2007
10,271
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Midwest America.
When I built our house, we used radiant floor heating with a Viessmann boiler, zone controller, and have Unico air handlers. As a result I have two thermostats. One heating, one cooling. I was told that the systems, from the thermostat perspective, are incompatible. We also have, for that time, a top of the line programmable thermostat that the numbskull installed for us, that isn't being used properly, because it only gets used for cooling.

What is the compatibility issue between the two systems, and could the Nest (cute name BTW) replace both thermostats so I don't run the risk of having both systems active fighting each other? This whole HVAC is somewhat beyond greek to me. I thought that a thermostat was a thermostat and they all worked across the many devices... (Does Nest offer any support as far as compatibility?)
 
Tomorrow

Tomorrow

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PinkyMacGodess said:
When I built our house, we used radiant floor heating with a Viessmann boiler, zone controller, and have Unico air handlers. As a result I have two thermostats. One heating, one cooling. I was told that the systems, from the thermostat perspective, are incompatible. We also have, for that time, a top of the line programmable thermostat that the numbskull installed for us, that isn't being used properly, because it only gets used for cooling.
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That arrangement isn't a deal breaker. You would have to manually turn off one system when you don't need it (for example, turn off the heating system when it's hot outside), but that's not uncommon.

What is the compatibility issue between the two systems, and could the Nest (cute name BTW) replace both thermostats so I don't run the risk of having both systems active fighting each other? This whole HVAC is somewhat beyond greek to me. I thought that a thermostat was a thermostat and they all worked across the many devices... (Does Nest offer any support as far as compatibility?)
Click to expand...

I looked through the Next website and it mentions manually switching between cooling and heating mode, but it also lists a mode which seems to allow for automatic switching. The thermostats in my house have to be set manually to heating or cooling, but this usually isn't a problem (it isn't very often 30 degrees in the morning and 90 in the afternoon).

As far as compatibility goes, there's a web app on their site that lets you check which wiring you have in your thermostat to tell you whether the Nest will work with it. If you're really not able to use one thermostat for both systems it could be because they were installed as two separate systems (one is not aware of the other), and in that case they would most likely each need their own controls.
 
A

aristobrat

macrumors G5
Oct 14, 2005
12,292
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Tomorrow said:
The thermostats in my house have to be set manually to heating or cooling, but this usually isn't a problem (it isn't very often 30 degrees in the morning and 90 in the afternoon).
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Where I live, late April thru mid-May has daytime temps in the mid 80s, but nighttime temps in the lower 60s, so if you don't remember to flip the thermostat from AC to HEAT before you goto bed, you can wake up with a very chilly house! :eek:

As happy as I am with the cost savings from my Honeywell programmable thermostat, not having to remember to manually flip between AC/HEAT was the reason I bought it. :eek:

I was bummed to see that if you put the NEST in the mode where it automatically flipped between AC/HEAT, you lost functionality (at least with the initial version of their software).
 
Tomorrow

Tomorrow

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aristobrat said:
I was bummed to see that if you put the NEST in the mode where it automatically flipped between AC/HEAT, you lost functionality (at least with the initial version of their software).
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It looks like you only lose the learning aspect of its functionality - it can still be programmed in that mode.

I wish I could have more of those 80/60 days here. I'd turn the A/C off and leave the windows open. :cool:
 
Love

Love

macrumors 68000
Jan 20, 2007
1,782
4
Just southeast of Northwestshire
Couple questions:

1) Has anyone happened to notice if you are able to switch the temperature readout to metric/celcius?

2) I don't have any AC system in my home -- basically none of the houses on my block do. Is that an issue for Nest's functionality?
 
HE15MAN

HE15MAN

macrumors 6502a
Original poster
Sep 3, 2009
955
14
Florida's Treasure Coast
Do you guys think its easier to setup your own schedule for it, or for it to learn on its own?

Also, I cannot login to the web interface, but the apps work fine. I have tried IE and Firefox. Anyone else has issues with this?
 
Tomorrow

Tomorrow

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Love said:
2) I don't have any AC system in my home -- basically none of the houses on my block do. Is that an issue for Nest's functionality?
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Why would you buy a thermostat? If your plan is to control a heater with it I'm sure you could get it to work, but otherwise I'm not sure why you'd bother.
 
MacNut

MacNut

macrumors Core
Jan 4, 2002
22,995
9,973
CT
HE15MAN said:
So the AC goes into sleep mode after 4 hours of no one walking by it? I dont think I will have that problem downstairs. My upstairs unit may, but I am only up there once a day or so anyway.
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What does it do when you are sleeping but want the house to stay warm or cool?
 
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