Should Your Thermostat Be Cloud Connected?

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The idea of a wi-fi enabled thermostat that you can control remotely through your smart phone or computer is very appealing. Unfortunately most of the wi-fi thermostats I've run across have one major flaw. They require the use of an internet or cloud based system for remote monitoring capabilities which leads to a lot of problems and concerns. I've had my Honeywell Wi-Fi Programmable Touchscreen Thermostat RTH8580WF installed for over a month now and here are my issues with not only the Honeywell thermostat but other similar thermostats that can only be used with a 3rd party web service.

Cannot Access Thermostat Directly

The biggest drawback is that while the thermostat can communicate on your wireless network, most of these cannot be accessed directly. The Honeywell RTH8580WF I own for example is not accessible on my local home network.

It took me a while and some effort getting the thermostat installed because I needed to run a new thermostat wire to connect the C wire but after that everything was going well. Then Superstorm Sandy hit my area. I wasn't hit as hard as others but I did have some damage to my home and other issues to deal with.

Luckily I didn't lose power but I did lose phone and internet service. I spent most of the day after the storm assessing damage, taking pictures, watching workers, cleaning up debris, doing some maintenance and temporary repairs.

That evening I crawled into bed cold and tired. I was about to step out of bed and head down to my thermostat to raise the temperature until I remembered I have a thermostat I can remotely control with my phone. As I was reaching for my phone I remembered my internet service was down due to the storm. I had just installed the thermostat the previous day, spent time and money (close to $50 for fish tape, wire and transformer) to get the thermostat installed before the storm hit and now the first time I really wanted to use it, I couldn't. It was a real let down.

All the other devices on my network worked fine, even wi-fi connected ones such as my phone. I was able to upload photos and videos to my media server from my phone all day. These thermostats that require an external web service cannot be remotely controlled when the internet connection is down. Even if you're connected to the same local network.

This was a big dissapointment for me because I had planned to develop some software to monitor the temperature in my home. At some point this functionality may be available through the Total Control Comfort website but it's not there yet. Even if it does get added to the portal I'm still not comfortable letting a 3rd party have access to personal information such as my home's temperature.

Privacy Concerns

The web based portals that allow remote control of the thermostat also appear collect information about your schedule, indoor and outdoor temperature as well as any changes you make to your thermostat. In the case of my Honeywell thermostat, it was sending information to Honeywell's webservers over 100 times a day.

While the connections appear to be secured by SSL and the web service is password protected there is always the possibility that the information can be accessed by those not authorized to do so. Knowing how you set your thermostat can allow someone to guess when you are or aren't at home. The information can also be accessed legally if subpoenaed. What happens if there's a crime committed and someone misidentifies you at the scene? You claim you were home alone when you would normally be at work. Instead of raising the temperature you put on a sweater or stayed in bed sick. Authorities request your thermostat history and sees you didn't increase the temperature which may poke a hole in your alibi in some people's eyes.

These may seem far fetched but could be a big problem if they ever happen to you. There are other ways that the information may come back to haunt you.

Targeted Advertising

In the connected world we live in, information is very valuable. Think of a company like Google. It provides a free service to the masses but it uses the information it gathers from those users to make billions of dollars. They monitor usage and search patterns to be able to provide targeted advertisements which advertisers are happy to pay for.

The same can be done with your cloud based thermostat. Does your home take longer to heat up than other homes in your area? That might be valuable information that can be sold to local contractors in your area or other service providers and they can even know the best time to call. Does your thermostat schedule indicate you work at night? More advertisements can be tailored for you. 

But your phone number is on the National Do Not Call Registry so you don't have to worry about that right? Wrong. Any company you currently have a relationship with can call you unless you specifically tell them not to. All it would take was for your thermostat service provider to do the calling on behalf of third parties or they might just send you junk mail.

Carefully review the Privacy Policy for the thermostat you choose if it only has an option for web based access. Unfortunately this information is not provided when you make the purchase.

Possible Future Fees

Honeywell's Terms of Service indicate that they have the right to charge a fee for use of their web based portal. Another company already has instituted a monthly fee to remotely control the thermostat. Whether fees are charged or not will depend how much money the company can make off the usage statistics and other personal information it gathers. All the internet connected computers and employees it takes to run the web portal aren't free.

If the web portal ever gets discontinued for whatever reason or fees are instituted that you do not wish to pay, remote control of the thermostat through the Internet is gone.

Needs A C Wire

This isn't such a big drawback, especially if you have a newer HVAC system but in older homes it may require running additional wiring. My original thermostat only controlled my heating system and used 2 wires. I needed additional wires to run the power to the thermostat. The thermostat draws too much power to be run on batteries solely.

I contacted the manufacturer of my heating system and they informed me that it wasn't recommended to run the C wire off the 24VAC transformer. They claimed it would increase the load on the transformer and might cause problems including premature failure of the transformer. That meant buying an external 24vac transformer for the thermostat. Between the new wire, transformer and fish tape it wound up costing me close to $50 to run the new wires to install the thermostat. That's with doing all the work myself. If you hire an electrician or HVAC contractor to do the work, you'll have to pay labor costs.

Other Options

I don't like the idea of sending out my home's temperature information to someone else thousands of times each month so I was glad that the wi-fi features of the thermostat could be disabled. 

After looking around it seems the only wi-fi thermostats that allow you to access them directly are the Homewerks Radio Thermostat CT-30-H-K2 and CT-80-H-K1 wireless thermostats. Homeworks even provides an API that makes it easier to develop your own applications for them.

Hopefully the other thermostat manufacturers like Honeywell do the same.


  1. I'm surprised to find no other comments on the posting. This is the best information and agreement with my own sentiments that I could find. I'm amazed that "everyone" seems OK with sending out information about their home, personal settings and schedule to the internet at large (if anyone thinks that any company with a primary agenda to make profit is not the internet at large then you may disregard my comments). Thanks for the posting about alternatives!

  2. I am surprised no other comments as well. This is a huge problem for me. I want a wifi thermostat that does not use the cloud.

  3. I think proliphix made a hard wired thermostat with local ethernet control, but I don't know of any other. They sometimes show up on ebay but are usually pretty expensive. it could be connected with an ethernet to wifi adapter like those game adapters.

    1. I have a Totaline T1900 and I was able to connect to the serial port with a small ARM cpu board directly using usb to ttl adapter. I set up a web server and it's been working great for some time.

  4. Kinda worried that the Honeywell RTH8580WF and the RTH6580WF may go the way of the Hunter 44920 Universal Internet Thermostat although at least you can control the Honeywell with butttons. I have an old Honeywell security system and when they abandoned the platform, they even wiped out all information, such as manuals, from their website. Not just the control software, and no, they did not publish any control protocol. If I wanted a regular thermostat, I would have bought one. Actually, I still have my trusty old Venstar, but it doesn't have any interface capabilities.

  5. I agree fully with the comments of this article. I was thinking the same thing as my dad decided to install one here in the UK. My main worry for the future is not if they use my data to spam me with adverts. What I'm worried about is if these companies come to an agreement with the energy providers. I currently have one and the same provider for my gas and electricity. At some point in the future we will all have smart meters for the electricity. So imagine your energy provider analyses your thermostat settings and sees that your heating comes on while there is no electricity being used in the evening (from lights etc) and hence there is no one at home. They might then charge something like a CO2 penalty on top of the extremely high prices, because you are heating up an empty home. They are selling this things by saying it will save money and its convenient but they don't tell us the real reason why all of a sudden there is a plethora of smart thermostats coming to the market.

  6. I was all ready to get a "Wifi" Thermostat when a comment from someone in a review stated that it required a 3rd party website to be able to control my thermostat from my smartphone. I thought it might have just been a mistake, but upon further research it's true. I simply can't believe that there is no direct interface from my local network.

    Most of the reviews and such even equate the term "Wifi" to the internet, as if there is no difference. Here is a quote from a review on the Honeywell site... " Of course, to make use of the Wi-Fi function it goes without saying you will need access to the internet. "

    This is hugely disappointing and frustrating. Security and privacy simply have no meaning anymore. This is a good article, but it's the only one I can find that addresses this "elephant in the room". I'm sure the "social networking crowd" simply don't even understand our concerns here.

    If anyone comes across any more devices that we can actually control over "Wifi" ,please post that info here.

  7. I bought a Honeywell WIFI thermostat with the assumption I could control it through my LAN. I was extremely POed when I found out I had to send a signal 1500 miles round trip. They should not be calling this a WIFI thermostat. The term "WIFI" is misleading. WIFI doesn't mean you need internet service. I've hounded Honeywell to no avail and only received one very rude response. Been looking for a script or API for the last year and haven't had a bit of luck. I'd like to stick this therm right up Honeywell's wazoo.

  8. I too bought Honeywell thermostat without doing as much research on such devices as I have had in the past. I got punked. Would be nice if there was a way to just set the setpoints, switch from heating and cooling mode without going through the mothership. I would think this would be a fairly easy thing since your typical $30 Linksys router incorporates a webserver where you can control all aspects of the router without having to go through Linksys. Hell, even your $100 Trendnet IP PTZ security cameras have this same capability. Or is it that all of these HVAC thermostat manufacturers are future-proofing their business such that they can come out with a new model next year, discontinue support for the old model and force money out of your wallet for an otherwise working piece of electronics that you paid good money for? I think busting the protocol and coming up with a Hombrew or jailbreak is in order, but alas this stuff is so niche right now, so these companies might as well milk it.

    1. I am more worried about thermostats usage becoming part of the per kilwatt pricing equation such that power companies can maintain their bottom line. Kind of like how travel agencies such as Expedia use cookies, ip addresses and other unique identifier shenanigans to set your personal price.

    2. well don't worry about that part of it because they already have remote access to most electric service meters with plans to eventually have them all on remote access in the whole

  9. Thanks for the info.

  10. This is exactly what I was looking for. I bought a Nest, found that there's no "hold temperature" function, despite page after page of requests for it on their site. Their site was down twice in the week that I had it, so I couldn't remotely control it. It went right back to the store. I just ordered the CT-80 thanks to this site. I wouldn't have known it exists without you. Thank you!!!

  11. I found this post while researching other similar views and processing a return/refund request for my Honeywell Wi-Fi thermostat. I did not know it required a cloud connection until I finished the physical installation and tried to finalize the Wi-Fi connection, at which point registration is required. No problem, I thought, until I read the Honeywell privacy policy, which points out all the information they collect. When combined, it is nearly everything I don't want a company like Honeywell collecting, and I know damn-well they are not in a place to protect this information from hackers either. F*** this... going to find a thermostat that has a usable API and will just figure it out on my own... Raspberry Pi thermostat project commence!

    1. Thank you for your post of information... I wonder which WIFI thermostat you found that does not connect to the cloud and mfg servers? I too am searching for one. So far i've come up empty!
      respond to: please...

  12. I think people are not educated on how these products work. Privacy is a big concern. Now a days coolness trumps everything without really knowing how personal data is collected. All device manufacturers need to open their device for local control. There is no reason why somebody have to go to the cloud and back just to control a thermostat or bulb in my home. Google Nest is the worst product from a privacy perspective. I hope alternative companies provide devices that supports privacy.

  13. Privacy does seem to be lost to alot of people today. I'm not a paranoid, but I absolutely hate the idea of my homes information going out on the internet and collected, used, monitored by a 3rd party, completely unnecessary. It can only be used against you in the future. Govt's come to mind, oh, we see your not using energy the way we want you to, here's a nice tax for you.

  14. I decided to buy the radio thermostat specifically because of the LAN API. It connects to a remote control server, but at least everything can be configured locally via the REST API as well. My grip is that it has no authentication and it doesn't look like they're supporting it, home depot has discontinued it and I'm not sure how much longer they'll be around.

    There's a lot of awesome home automation tech coming into affordable price ranges, but I hate the idea of getting locked out of my own systems because of corporate interests have decided that owners shouldn't be in control.

    Take a look at what happened to Revolv automation product line after they were squired by Nest (now Google (now Alphabet)): google nixed the cloud service and everybody's home automation units were bricked forever. Google didn't release a programming API or unlocked firmare, the service just went black and these things had to go in the trash.

    This is exactly why we need technology to be unlocked & open source, I would have bought an open source thermostat in a heartbeat, but I couldn't find a single one. I could build one out of a raspberry-pi, but I really want something pre-fabricated & professional.

  15. I like Nest thermostats over Ecobee

  16. WOW. Great INFO!! I am an IT Professional. It is very refreshing to see someone say exactly what I have been thinking for a very long time now. I am constantly amazed and frightened how eager the average consumer is willing to trade their privacy for "Easy". All companies want recurring income but they also know before you ask people to pay monthly fees you need to get them to invest into the "Cloud" soo deeply that it is too expensive not to just pay the fees. That is when fees will start appearing. Do we really need somone elses "Cloud" to access our: DOOR LOCKS?!, appliances, cameras, thermostats?!? More people need to demand the option to set up these things on their private network. Also just a mention that I think some people may overlook: Right now the benefit is very trivial to hack any of these "home Automation clouds", but as more and more people enter these systems it will be more appealing for hackers to target these systems thus gaining multiple access capabilities via the effort to access one system.

  17. I'm not a conspiracy nut or anything but "Big Brother" is here and its not the We are paying "Big Business" to set up the infrastructure and standing in line impatiently waiting to give them the "Keys"...rotfl I'm just saying.....

  18. Thanks for your help! I need a home thermostat with a dedicated , small radio frequency remote just for in-home use. Connecting to internet, using 3rd party networks, etc is unnecessary but hard to escape today. (The X-10 systems used 25 years ago had no need for fool internet connection.) Internet access for control of home electrical devices also allows utility companies to manage your home! Think I' kidding? Read up on HAN (Home Area Networking). It's already a trend in northern, inland California.