Affordable WiFi Thermostat?

Update 11/20/2010: Finally, these things are available now and at Home Depot for $99!  The same thermostat under the Homewerks brand seems to be available at Amazon [amzn] for about the same price as Home Depot; take away tax and add free shipping and the price is comparable. See my other blog post on the subject.  Read on for the original post…

I’d been looking for a WiFi thermostat that was affordable for a while; most seem to be vaporware or very expensive – but the CT30 from the Radio Thermostat Company of America looks like it may just fit the bill.  It apparently has a Gainspan low-power WiFi chipset, and the online store shows it at $99.  Unfortunately, shipping is $53 – overnight from China!  But they tell me they’re working on fixing that, and they should be available to ship by next month.  Apparently there is also an API to talk to the device, but documentation on that doesn’t seem to be available yet either.  I did manage to find manuals for the more sophisticated device, the CT80, so it appears to be more than vaporware – I’ll be keeping an eye on it for sure.

Update 3/4/2010:  Now it’s $119 … still backordered, still listing $53 shipping.  Argh.

Update 4/19/2010:  Now it’s $119 … and still backordered, still listing $53 shipping.  Argh Argh.  Losing faith!

64 thoughts on “Affordable WiFi Thermostat?

  1. Thanks Scott for the tip. Unfortunately the “CT30” is backordered as of 30-Jun-2010. (Same as RTOA) Where you able to order one at the beginning of the month?

  2. The CT80 (at least) is now available from RTOA again. Mine was delivered within 10 days of ordering, though the Thermostat shipped directly from China (!) and the WiFi module separately from CA. As far as I can determine from the (rather limited) documentation on the WiFi module, you can only control the thermostat via the internet (by Registering it at There is no apparent way of linking to it directly within your home network – or at least none provided with the device. Obviously, you can browse to the ourhomespaces site and login there when you want to do anything, and the display and control options there are reasonably comprehensive, but that seems like a rather strange way of doing things. I had assumed that there would be a documented direct HTTP or FTP interface of some sort, but browsing to the module’s IP address produces only a time-out error. I have sent email to the ourhome spaces people enquiring about this – I will post again if I get a useful response.

    • Peter, thanks for the update! Seems the cheap one (CT30) is eternally out of stock…

      Yes, this device seems to be very focused on the subscription model, which kinda sucks, IMHO. RTOA / ourhomespaces / intwine / enphase are all following that model.

      I’m of the firm belief that devices like this should have open data access; 98% of buyers aren’t hackers and would probably be glad to pay $20/year for pretty flash graphs, but folks like us would like the raw data too! Maybe the fear is that some other subscription service would undercut them for the masses if the access were open…?

  3. It turns out that I was doing the RTOA/ourhomespaces folks something of an injustice. I initially had trouble with a Yahoo Widget that you download from the ourhomespaces website and thought that its only function was to hook up the WiFi module with the site (their documentation needs serious work!). In fact, once I got thiings working properly, it turned out that the widget also allows you to do from the desktop most of the things that you can do from the control panel on the website. I also made contact with someone at ourhomespaces, who has offered to send me the protocol definition for the device. The widget’s JavaScript code isn’t encrypted in any way, but it might as well be for all the sense I can make out of it!

    Also in fairness to the ourhomespaces folks, they haven’t asked me for a subscription (yet?!).

    Having said all this, I, too, would like to have direct access to my data, and look forward to seeing the protocols.

  4. Hello there. Dropping in on the conversation. I have been on the lookout for these things for a loooong time. Even let go at one point, but I’m picking it up again. Thanks for your info, let us know how your stuff turns out ! I will experiment on my end, will let you in on what I find.

  5. …here’s a little note : I’m from up north, were most thermostat are high voltage in-line units. Hence, not only am I looking for what looks like vaporware, but even more so since high voltage will most likely

  6. Well, I do have the documentation, and I now have a VB.NET Class to read and control the Thermostat about 80% completed. The device’s (UDP) interface takes me back to my days of programming real time data acquisition and control applications for DEC micros under RT-11! Because it is a UDP interface, you need to be able to program in a language that allows you to get down and dirty with sockets – you can’t just use HTML and JavaScript and/or WScript, so there is no straightforward way of writing a freestanding Windows Sidebar gadget (which is what I had hoped to do). I will be using an approach that I use to summarise and display the output of my TED whole-house power monitoring kit – run a VB.NET application in the system tray to do the data-acquisition and processing and use the Registry to transfer the data to be displayed to a simple sidebar gadget.

  7. On the high (I assume that means mains level) voltage thermostat issue, one approach would be to install an appropriate 24 VAC transformer near your furnace, with adequately rated relays set up across the mains control lines – then you can use any 24V thermostat to switch power to the relay coils.

  8. Hi Peter –

    are you planning to open source / share your VB .NET class and code?

    I’m particularly interested in how you are controlling your thermostat from a .NET app


  9. I saw a 3M50 (339-052) Wi-Fi thermostat at Home Depot for $99.00. They only had three, but i assume they will get more.

    • Interesting, what brand? I can’t find it on the website…

      On edit – oh I found a Filtrete 3M-30… hmm “WiFi capability – no” ;)

      These things clearly are all made by the same mfgr aren’t they!

      On edit#2: 3M/Filtrete 3M-50 page on! Very interesting … pity I just bought a new $50 thermostat w/o wifi :)

      On edit#3: I wondered if the wifi module was extra, but this youtube video seems to imply that it’s part of the package. Nice!

  10. Great Topic. I am also looking into this CT30. Peter, did the $99 one come with the Wifi Module? Or did you have to buy the WiFi separate?

    • @Dan – Ah, so it is finally in stock at RTCOA! And with only $9.95 shipping now, cool… keep me posted on how it works out!

      One thing my new (non-wifi) thermostat has is the ability to start early to hit the setpoint at the specified time, rather than turning heat on at that time. It’d be a nice feature … I can’t tell if these ones have it.

  11. I have two installed at my house and they are really cool. The iPhone app is very easy to use. We went out last night – and I made sure my heat didn’t turn on! That must have saved me a least a few $$.

    There isn’t an anticipation factor – but I’m not sure if I would want one. There are so many factors that could contribute to the timing of the when the heat should turn on – that it seems that this would be an easy way to accidentally waste energy.

  12. Dan, so you got the Home Depot / 3M versions installed? How does the software setup work, then? Most people seem to want to sell you a service, is that what’s going on here?

    As for the anticipation (if that’s the right word), I dunno. I’d just be setting the thermostat earlier anyway, if I wanted it to actually be warm at 7:30am vs. warming at 7:30am. I have to say, it’s been nice to have it comfortable when I wake up. In the past, if I got it wrong, I’d wake up to a cold house that would be warm when it was time to leave… I think that’s wasting some energy too. :)

  13. 3m-50 thermostat homedepot 99 smakers

    but were can I get one I don’t need to register like a firearm with big brother ?

    I’d like to control my own hvac and internet access since I pay for it.

    No Dalton red neck zone

    • You can order it online at home depot, or some stores are getting them as well.

      You have to sign up for an account so that it can contact the outside world, and then you can control it. You’d need to read the privacy policy for the account if you re worried about big brother, I have no idea. If I get one I plan to do a little bit of programming to talk to it directly myself.

  14. The software setup was pretty easy – if you setup your WiFI router, you can setup the stat. When you take it out of the box, it starts as a Hot Spot call “Thermostat”. Then you connect to it and open up the gateway web address (just like you would to configure a router). Next it does a scan for networks, I picked my home network, entered in my highly secure network password, and the thermostat booted up on the network.

    Once you are on the network, you run your iphone app and there is a registration process that happens. They have a PC program you could use if you don’t have an iPHone/ipod touch/iPad. That was it.

    As for service – the thermostat is pinging out to a server every minute or so. I’m sure it works like this to avoid all of the issues with dealing with firewalls and port forwarding. The iPhone app talks directly to the thermostat when on the local network.

    I know I’m getting lazier with this thing installed. It got hot in the kitchen when I was cooking yesterday, so I used my phone to turn on the fan to circulate air. Those 5 steps to the thermostat would have been too much!!!

  15. I should have mentioned – there are no service fees. I can control my thermostat from anywhere in the world for free! I’m sure there will be additional things Radio Thermostat will sell down the line -but basic control is gratis.

  16. I got one at Home Depot too. US$99.95, no monthly fees…. easy to install, I did have a question and went to the webpage the gave me a link to YouTube videos. they had videos on lots of topics.

    I have not looked everywhere, but $99.95 seems like the lowest price and 3M seems like the only real brand name in the game.

  17. poliphix is a much more expensive unit
    I also checked out Ecobee, neat but again over $300
    To me it looks like the 3M and the Radio Thermostat are very similiar, but the RT has three different units available, (mama bear papa bear, and the baby bear) baby seems closest to the 3M, but all have the same basic WIFI functionality

    • Randy – yep, they are all versions of the same thing. Even the cheap ones at home depot have the sockets for the wifi module , but that doesn’t seem to be available at a reasonable price anywhere … yet.

  18. Hi there!

    Do you know if ever those wifi thermostats work with baseboard heaters?
    Will I only need to install a 240/24v adapter?


    • That would be a no. While there is no mention of it (that I saw) on Amazon that it doesn’t work with baseboards, I just confirmed on page 12 after purchasing one: “It cannot be used with line voltage systems” which I’m pretty sure means baseboards. The wires I have connected to my old thermostat are black on both terminals. It looks like my thermostat is simply an interruption in the “hot” wire and when the mechanical device changes with temperature, it completes the circuit sending juice to the baseboards. Back to the drawing board.

      • Ken, sorry to hear that. Hey, at least I did give links to the manuals last October. ;) But it’s a 24V device, if what you need is something to switch line voltage (120V or higher) directly, then I don’t think this is it.

        However, I think you can get relays so a low voltage thermostat can switch the relay, which switches the baseboard. Something like the Aube RC840T-240 maybe? I can’t vouch for that, never used anything like it, but a google search indicates something like this might work – “The RC840T Electric Heating Relay is designed to control a line voltage resistive load from a low voltage thermostat.”

  19. Home depot

    Filtrete WiFi Enabled Programmable Thermostat
    Model # 3M-50     Internet # 202352449    
    Store SKU # 339052    

    Ships FREE with $249.00 Order
    Average Customer Rating
    4.2 out of 5

  20. Hi guys,

    As excited as everybody else, I purchased my wifi thermostat at a local home depot near my 2nd home in Scottsdale, AZ. I then proceeded to spend an estimated 2 full days installing, tweaking and testing (believe it or not I enjoy doing this stuff), and here are my findings:

    – Installs easily as advertise
    – Easy to get the WIFI connected and registered
    – Great documentation and youtube video

    – Display issue partially conceals current target temp – (I tried Chrome and IE 8 – not really a big deal)
    – Must be managed through a web portal (although this is free)
    – Away function requires that you select Heat or Cool, i.e. cannot manage both
    – web UI not terribly feature rich (apparently this is being worked on)

    – Although easy to connect to the network initially, the device over a 5 day trial period LOST CONNECTION AT LEAST 1-2 TIMES A DAY and needed a physical reset each time (not easy when living in another state)
    – The Web UI does not have any indication of connection status whatsoever. The day after I returned it to home depot for a refund, I logged into the web UI out of old habit and saw that my apartment was at a comfortable 69F (even though the device was powered off and presumably on its way back to the manufacturer) :-)
    – There is supposed to be an email alert that kicks in when connection is lost. This never worked during my 5 day testing period.

    Anyways, I found posts on the manufacturers forum saying that they had detected lost connectivity issues in a \small subset\ of shipped devices. I posted my findings similar to this posting, with what I considered to be fair feedback, but they apparently did not want this post out there as it has not yet appeared in the forum.

    I will be waiting for hardware and software improvements on this one.


    • dl – hm, bummer. I have had posts on the forum take a little while to show up, but I never got the sense anything was being filtered or censorsed. The firmware in the wifi u-snap module is field upgradeable as I understand it so I’m surprised they didn’t give you something new to try.

  21. Been threatening to buy one of these from Home Depot. What are you guys doing as it relates to the need for 24v ac supply on Home Depot model. Not sure my system has 24vac available. Also don’t know much about these things.

    • Json – I’m also a little hung up on the 24VAC – but if your current thermostat has a “C” wire attached it probably has 24VAC. My mystery is I seem to have more like 32VAC and near as I can tell from tracing wires around the basement, there’s a transformer buried above a ceiling somewhere…

  22. Hello All.

    For someone who needed to spend an hour on the phone to India for help hooking up my router is this a bad idea for me?

    I am sure this technology will become much more user friendly in the future but it seems like you need to be a bit of a programmer.

    I like the idea of controlling the temp remotely, but I can’t be having problems like losing control of the furnace, especially here in Canada.

    Will this only work on an iphone/ipad etc. or will it work from my Android phone as well? Can I run it from my Android and my wife run it from her blackberry concurrently. For example, after I leave the house I turn the temp down and then when my wife is leaving work she can turn it back before arriving home?



    • Hi Chris – I’d ask on the radiothermostat forums if nobody answers here… I actually don’t have one yet and nobody has sent me one for free in exchange for all the buzz, either…. :)

  23. Agree with with @mrwassen above. It just not reliable enough at this point.
    I will return it in a couple of weeks if there is no firmware upgrade release that fixes the problems that I am having.

  24. You certainly can change the thermostat mode (Heat/Cool/Auto) remotely (i.e. the communications & control protocol supports this), so fixing their software interface should be easy. I can see why they didn’t make it a high priority, particularly since the Auto setting works pretty well in crossover seasons.

  25. CT50 V1.09 / Firmware 1.04.52 ===> Home depot has these, racked up – for 99 bucks + Kalifornia Commie Tax of ~9%, in stock. Works great, just need power. Read like a mad man, watched the videos (youtube*), and went through the base installation, WiFi and lastly the operations manuals. My wife actually did most of the setup – including the initial WiFi – only to learn that her husband hadn’t gotten 26V (ac,dc) to the right terminals (C & Rh). The prior setup was a 2 wire connection and the W and Rh were reveresed (duh), so I had to swap them. Done, power up and WiFi were ON. The RTA Customer Service gal got me on that (pull batteries, and if the display goes blank, the power isn’t right). Fixed that, and we were off to the horse races, and everything was a WiFi Snap (all puns intended) at that point.

    The I-Phone Ap DOES ALLOW REMOTE SELECTION OF HEATING OR COOLING, under the \mode\ option, so i’m not sure that the comment from Paul Anthony is correct at this juncture.

    We’ll buy a second unit, today, and put it in our lakehouse this weekend. For 99 bucks, you just can’t go wrong.

  26. The connection issues have been greatly improved with the subsquent firmware release (now Firmware 1.04.52). Not perfect but they are making progress .

  27. Emphasis on not perfect . I am still having connection issues.

    \The connection issues have been greatly improved with the subsquent firmware release (now Firmware 1.04.52). Not perfect but they are making progress .\

  28. I would say it is still vaporware for some of us. It loses connection with the server and then you have to do a manual reboot. This is not a remote device yet. There have been complaints for over a year and they have not fixed the issues.

  29. Will no company make a device that I can operate entirely on my local LAN? I do not want to use a 3rd party or worry about disconnects or “your free service ends on” messages. All I want is a simple to operate LAN based PC app that I can run on my local PC at home that is secured from the outside world.

    I do not want or need a 3rd party monitoring my energy usage
    I do not want or need a 3rd party doing anything!
    I just want a thermostat that I can connect to directly and manage via IP.

    Why does this seem so far fetched? All of the manufacturers are the same “login to our website and monitor/maintain YOUR home” which I find ludicrous from a privacy and security standpoint!

  30. I bought one from Home Depot in April 2011 and installed it at our Summer home 3,000 milles away. I had been looking for a long time for a wifi control thermostat as I already have mutliple wifi camera for security at that location. The wifi thermostat is amazing, I can check the temperature inside the house at any time from any where. The reliability of the wifi is as good as my router and internet connection are. Plus the thermostat web site will send me an email if there is a break in the wifi connection which did happen a few times, no fault of the thermostat. Overall +++

  31. Installed the CT 30 in my home 10/2011. Remote connection via Droid and app were initially sketchy: in the last 8 weeks have not required a reset. I am using the free app, so my only cost is broadband into my home. Great device

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