Honeywell Digital Thermostat

[Raspy]

Raspy, you almost answered me question - now hold on, you cain't just say you don't like Nest - ye gotta tell us why. I've been researching them high dollar Nests since they first came out. I like the idea of being able to control it from anywhere for our other house. What don't ye like about them?

oh, and sorry about old Thoreau, but hey, here we are on high tech computers online and wantin' to be like that old boy...:thumbdown:

I've been out for a few days, sorry for the delay.

I can tell you a bit about the Nest thermostat.

First thing is that people buy them because they are spectacularly beautiful. People get captured and want one for that reason. Only later do they begin to look at the features and operation of the thing.

The original ones were worse than the new ones because they have tried to compensate for the problems. I've actually been wanting to consult with them and have a couple of connections with people that have friends or relatives working there. I've been cautioning people that want one and I am reluctant to install any of them. I've actually pulled a couple back out because they could not be made to perform well.

I have a very specific use for thermostats because I'm in the radiant heating business. I design, repair and install systems and have for 35 years. For all that time I've been trying to arrive at the perfect design and operational program.

Everyone used to say that in-slab radiant systems should just be set and left alone. That they responded very slowly and should not be programmed or turned up and down. This is not the case. If you do that, the system will run as needed all night and stay at the set point. Then in the morning when the day begins to warm up, cooking starts, people are up walking around and the lights go on, etc, the house will continue to warm up and overshoot the set point by 10 or 15 degrees. After being off all day and the slab gradually cooling, evening comes and the temp drops. By the time the system comes back on it's too late and the temp drops below the set point and doesn't recover until late at night. Bottom line: If you have a constant setting you have a wildly fluctuating room temp. If you program the thermostat with 4 settings per day you even out the temp, reduce the bill and make the house much more comfortable.

Nest uses room temp for it's calculations. If it determines that you walk by it a 7AM each day, it decides to make the house warm at 7AM. To do this with radiant it keeps turning the system on earlier and earlier until it achieves that goal. Pretty soon it's on too much at night getting ready for the morning and the overshoot problem gets worse and worse The bill goes up and the comfort goes down.

The proper way to heat in the morning is to set the stat to come on 1 hour before you get up and turn down when you get up. Not when you leave, but when you get up. This gives the floor a shot of heat to greet your feet, but doesn't overheat the house.

This is a brief overview of the problem and Nest is working on it to measure the overshoot and cut the heat early, but that doesn't work because the morning warm floor greeting is compromised.

The next thing is that they are power stealing thermostats and cannot work without finding 24 volts. Some systems don't have that available or the wiring is not adequate. Usually it is, but not always and it means we have to supply a separate 24 volt supply to the stat and not interfere with the system operation. Sometimes it requires that a relay be installed.

People buy the beauty. They are captivated. And that's the funny part. Somehow, more beautiful must mean much better performance.

If you have a simple forced air system with one zone and you have a very predictable schedule, good, it will work fine. If you want to marvel at the fancy thing on the wall, in that previous example, all the better. They are pretty.

But if you want a cost effective thermostat and have other things to do, or if you have radiant heating, you may not be very well served by Nest. And that's too bad. It was designed by folks that really don't get how heating works. Young aggressive engineers that don't have enough real world experience in that area, but do know how to make a spectacular wall display. And part of their goal is to connect your home to their office and monitor your performance. This will give them a chance to warn you of possible problems, share in your savings, report to the utility if your system is less efficient than your neighbors, etc. A much bigger picture than simply providing a product to you, to be your little helper there on the wall.

All this and I haven't even tied in how to operate a solar system in conjunction with a gas system and the thermostat requirements for that.

 

[MacLawn]

Thanks, Rasp. Not radiant heat for me, no solar nor nary plans for either, I don't like ugly, but ain't turned by nary pretty thermostat for sure. So, all ye negatives don't affect me. You can see I started a thread to ask people who are actually using one to see what they say. One so far is using, and likes it. I think it'll work great for what I need. My present high tech Carrier programmable thermostat is about as easy as working on a computer running DOS. Ridiculous, so it's just set on Hold.

Thanks again, Rasp!

 

[3930dave]

I've been out for a few days, sorry for the delay.

I can tell you a bit about the Nest thermostat.

First thing is that people buy them because they are spectacularly beautiful. People get captured and want one for that reason. Only later do they begin to look at the features and operation of the thing.

The original ones were worse than the new ones because they have tried to compensate for the problems. I've actually been wanting to consult with them and have a couple of connections with people that have friends or relatives working there. I've been cautioning people that want one and I am reluctant to install any of them. I've actually pulled a couple back out because they could not be made to perform well.

I have a very specific use for thermostats because I'm in the radiant heating business. I design, repair and install systems and have for 35 years. For all that time I've been trying to arrive at the perfect design and operational program.

Everyone used to say that in-slab radiant systems should just be set and left alone. That they responded very slowly and should not be programmed or turned up and down. This is not the case. If you do that, the system will run as needed all night and stay at the set point. Then in the morning when the day begins to warm up, cooking starts, people are up walking around and the lights go on, etc, the house will continue to warm up and overshoot the set point by 10 or 15 degrees. After being off all day and the slab gradually cooling, evening comes and the temp drops. By the time the system comes back on it's too late and the temp drops below the set point and doesn't recover until late at night. Bottom line: If you have a constant setting you have a wildly fluctuating room temp. If you program the thermostat with 4 settings per day you even out the temp, reduce the bill and make the house much more comfortable.

Nest uses room temp for it's calculations. If it determines that you walk by it a 7AM each day, it decides to make the house warm at 7AM. To do this with radiant it keeps turning the system on earlier and earlier until it achieves that goal. Pretty soon it's on too much at night getting ready for the morning and the overshoot problem gets worse and worse The bill goes up and the comfort goes down.

The proper way to heat in the morning is to set the stat to come on 1 hour before you get up and turn down when you get up. Not when you leave, but when you get up. This gives the floor a shot of heat to greet your feet, but doesn't overheat the house.

This is a brief overview of the problem and Nest is working on it to measure the overshoot and cut the heat early, but that doesn't work because the morning warm floor greeting is compromised.

The next thing is that they are power stealing thermostats and cannot work without finding 24 volts. Some systems don't have that available or the wiring is not adequate. Usually it is, but not always and it means we have to supply a separate 24 volt supply to the stat and not interfere with the system operation. Sometimes it requires that a relay be installed.

People buy the beauty. They are captivated. And that's the funny part. Somehow, more beautiful must mean much better performance.

If you have a simple forced air system with one zone and you have a very predictable schedule, good, it will work fine. If you want to marvel at the fancy thing on the wall, in that previous example, all the better. They are pretty.

But if you want a cost effective thermostat and have other things to do, or if you have radiant heating, you may not be very well served by Nest. And that's too bad. It was designed by folks that really don't get how heating works. Young aggressive engineers that don't have enough real world experience in that area, but do know how to make a spectacular wall display. And part of their goal is to connect your home to their office and monitor your performance. This will give them a chance to warn you of possible problems, share in your savings, report to the utility if your system is less efficient than your neighbors, etc. A much bigger picture than simply providing a product to you, to be your little helper there on the wall.

All this and I haven't even tied in how to operate a solar system in conjunction with a gas system and the thermostat requirements for that.

Overshoot and Undershoot.... too bad I'm so far away from you Raspy, otherwise I'd buy you a few of your favourite beverages and pick your brains a bit more...... I find many traditional commercial systems here (non radiant, just forced air gas as an example) will overshoot if outdoor ambient shoots up. Same for AC systems, if outdoor ambient drops fast.

The control loop seems too slow, but I've alway been puzzled why many systems aren't tuned to deal with this better. I think I know one factor.... will get to that in my second post.

I can see how the Nest came to be...... for many startup companies, the business model takes precedence (internal to the company) over actual hardware performance in the field - long term, that is likely where they'll make the big money. Taking my business hat off, and putting on my personal cap..... what you just walked through is a great example of why I'm in no big hurry to get into something like the Nest.

If I get enough RoundTuIts..... rolling my own remote monitoring system, well, that's another story.

I found your comment about beauty to be striking... there are some parallels with what one has to learn when passing through adolescence !

Rgds, D.

 

[3930dave]

Odd. Perhaps they had some versions with flaky firmware and as such made a blanket decision not to support them...

Aaron Z

Any service industry comes down to the truck roll....

Some (not all, Raspy is obviously not in this camp) HVAC guys do not want to get into configuring and tuning complex controls. Reasons can vary, but one of the problems is that as complexity ramps up, so do call backs by the customer - eats into profit.

I don't know exactly what Aaron and Dan do for a living, but my impression is that you guys are in/around the Tech sector, if not actually heavily immersed in it. Probably safe to say that you guys are more Networking aware than many folks. If guys like you are scratching your head over the Nest, where does that leave the average HVAC installer ?

Rgds, D.

 

[buckeyefarmer]

I put in honeywell internet accessible thermostats with my geothermal system. They interact via a remote honeywell site, I can't directly control the thermostat, only via their web site. However, that has not been a problem. I can monitor and control my thermostats from my smart phone or an internet connection, so I tend to change the temperature while sitting on the couch, instead of walking over to it. :laughing: Actually I tend to set one temperature and leave it alone. MIne runs off the 24V heat pump transformer, but has a button battery for backup. I looked at nest, but don't think it's good for a geothermal application.

 

[hawkeye08]

This discussion reminds me I need to troubleshoot the thermostat on my propane heating stove. A dirt simple thermostat (old with mercury switch) is either open or closed. It worked great for many years. Last year, things started acting up. I think it is in the stove end of things but have not looked into it. Its been too hot to mess with for the last couple of months, but the wife is going to want her heat before long.. now, where did I put those manuals 15 years ago... hmm.

 

[aczlan]

I don't know exactly what Aaron and Dan do for a living, but my impression is that you guys are in/around the Tech sector, if not actually heavily immersed in it. Probably safe to say that you guys are more Networking aware than many folks. If guys like you are scratching your head over the Nest, where does that leave the average HVAC installer ?

I am in the tech sector, but I wouldn't go with a system that could let someone else get at my thermostat from the outside world...
I am scratching my head over what the differences are between OpenWRT (for example) and the same box with the stock firmware. We have ~50 wireless access points providing public wireless access and those have worked for almost 10 years (that I know of). We started with WRT54Gs, then moved to WRT54GLs and are now rolling out the TP-Link TL-WR1043NDs for anyone who wants to add on.

Aaron Z

 

[dmccarty]

I am in the tech sector, but I wouldn't go with a system that could let someone else get at my thermostat from the outside world...
I am scratching my head over what the differences are between OpenWRT (for example) and the same box with the stock firmware. We have ~50 wireless access points providing public wireless access and those have worked for almost 10 years (that I know of). We started with WRT54Gs, then moved to WRT54GLs and are now rolling out the TP-Link TL-WR1043NDs for anyone who wants to add on.

Aaron Z

The Nest site says in regards to routers,

Here are some details on which access point makes models may have an issue with Nest when using the manufacturer's firmware.

The WRT54G is included in the list. It seems to me, if you had to support ONE router the WRT54G would be the ONE. :confused3:

Nest is using SSL with 128 bit encryption which are both kinda out dated at this point. TLS would be better as would a 256 bit key. They may be limited to mobile browser support for TLS and higher key strengths. :confused3: BUT, they still should be able to use higher security going from their server to the thermostat. I can't find any documentation that covers this subject on their site.

I simply do not like products that require me to use a website to operate MY equipment. What do you do if you loose the Internet?

Cisco tried to limit the ability to configure their routers from within the office/home. To allow full configuration, you had to register with Cisco and use their website to manage YOUR network in YOUR house/office. Furthermore, they had a backdoor into the router that allowed them to install what ever code they wanted on YOUR router without YOUR permission. :shocked: Cisco backed down on this ASAP once it became known but I won't buy a CISCO router. If they were stupid enough to try this once, they might try again.

What concerns me about Nest is that the thermostat is controllable by a third party. If Nest does not have very good security, someone can control other people's thermostat. Worse case, a break in on the Nest site could allow one person to control MANY different thermostats.

Later,
Dan

 

[RedNeckGeek]

dmccarty, you took the words right out of my mouth when it comes to the NEST. In my last home I had two thermostats interfaced to a laptop running home control software, and I could vary the temperature set points via a pre-programmed schedule, by pushing a button on any of several wireless keypads scattered throughout the house, or from a web browser if I wasn't at home. Worked nice, but it did have reliability issues. I was also working at the time, so a programmed schedule made sense.

These days I'm retired, my schedule is unpredictable, and I started heating with wood this past fall. I also have satellite Internet, not the most reliable connection. Also in a new house, and I looked at replacing the thermostat with a NEST, mainly to get remote control of the set point from an iPhone. Then I looked at all the "learning" stuff, the fact that it all depended on a fast, reliable Internet connection, and that it was focused on regularly scheduled on/off times, and I realized it wasn't designed for somebody like me and I'd be fighting it every day. And when I stepped back, I saw that most of the home control stuff I'd rigged in the old house was also centered around a fixed schedule, and now four years later I have yet to implement any of it in the new place. In my case at least, simpler IS better. Yes, once in a while I'll forget and go away for the day and leave the furnace or AC running in an empty house, but having a remote control feature wouldn't help if I don't discover the error until I return home, would it? Oh, the NEST is supposed to sense when I'm home, right? Good luck with that, as the thermostat location is in a part of the house that doesn't get much traffic, maybe one pass every couple of hours, and I don't see myself running a new wire to move it someplace more central.

Edit - Yes, Dan, that's another great point. Can you imagine the havoc created by a "worm" that scanned the net looking for NEST thermostats and randomly altered the set point? Or how 'bout when Google gets bored with home control, and assigns NEST to its burgeoning technology scrap heap, just like they did with their great web portal software? There goes $150 down the drain, and there's nothing even broken with the device itself! Or how 'bout when they push out a poorly crafted and untested "update" that creates reliability issues? We're talking real dollars in wasted energy costs across potentially millions of users. NO THANKS!

 

[3930dave]

I'm with many in this thread.... given the # of months the temperature is below freezing here, I have no interest in opening up my furnace control to the web.

What I can see myself doing is using something like Raspberry Pi, intially for remote temperature monitoring. Being able to get Out of Normal Range warnings remotely is valuable to me, and carries no huge security risks.

Rgds, D.