Honeywell RTH9580 Wi-Fi Thermostat Reviewed

Published On: July 1, 2015
Last Updated on: October 31, 2020
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Honeywell RTH9580 Wi-Fi Thermostat Reviewed

Adrienne Maxwell explores Honeywell's RTH9580 Wi-Fi Thermostat, which can be monitored and controlled remotely via Honeywell's own mobile app or compatible Wi-Fi-friendly control platforms.

Honeywell RTH9580 Wi-Fi Thermostat Reviewed

  • Adrienne Maxwell is the former Managing Editor of, Home Theater Magazine, and Adrienne has also written for Wirecutter, Home Entertainment Magazine,,, and other top specialty audio/video publications. She is an ISF Level II-certified video calibrator who specializes in reviews of flat-panel HDTVs, front video projectors, video screens, video servers, and video source devices, both disc- and streaming-based.

Honeywell-RTH9580.jpgHoneywell is a well-known name in the thermostat business, but I'd venture a guess it's not the very first name that comes to mind when I say "smart thermostat." Nevertheless, the company has become one of the top providers of smart, networkable thermostats, offering five different models ranging in price from about $100 to $250. These smart thermostats can be controlled directly through Honeywell's own mobile app and web portal, or they can be integrated into a compatible whole-home system, such as the Logitech Harmony Home Control system that I recently reviewed. Honeywell sent me the RTH9580 Wi-Fi thermostat ($199) specifically because it is compatible with the Harmony control system.

The RTH9580 sits close to the top of Honeywell's line of Wi-Fi thermostats, just beneath the top-shelf RTH9590 ($299) that adds voice control but is otherwise identical. This thermostat has a standard rectangular design with a grey finish and a 4.25-inch color touchscreen with a simple, easy-to-read layout. The Home screen provides date, time, outdoor temperature/humidity, indoor temperature/humidity, the current mode, up/down arrows to adjust the temperature, and an indication if you are currently following a schedule or running a manual mode. Four buttons along the top provide quick access to Home, Fan (on/auto/circulate), System (heat/cool/automatic/off), and Menu. Within the menu, there are all kinds of advanced adjustments to fine-tune the thermostat's behavior and onscreen appearance.

I've never installed a thermostat before, and the Honeywell Quick Start Guide made it very simple, with clear, detailed, step-by-step instructions for removing your old thermostat, properly labeling the wires (sticky tags are included), and installing the new Honeywell model. I installed the RTH9580 in less than a half hour with only minimal bloodshed (I scratched myself on one of the exposed wires).

It's important to stress that this thermostat requires a common C wire to receive its power; if your system lacks a dedicated C wire, there may be a workaround, but it will add a lot more difficulty to the installation process. Honeywell provides helpful instructions on its website to determine whether or not your system is compatible. The benefit of the C wire is that you don't need batteries to power your thermostat and, thus, you don't have to worry about them dying at the most inopportune time.

Once the thermostat is physically installed, you need to walk through an onscreen setup process, answering a few basic questions about your system and--most importantly--adding the thermostat to your home Wi-Fi network. The thermostat will do its job without being connected to the Wi-Fi network, but why pay more for a smart thermostat if you don't plan to connect it to your network? Next, you must go to Honeywell's MyTotalConnectComfort website portal to set up an online account (with a name and password) and register/link the Wi-Fi thermostat. Once this is complete, you can control the thermostat directly through the website portal from any location, and/or you can use the mobile app for iOS and Android devices. I downloaded the iOS version to my iPhone 4, signed in to the account I had just created online, and was all set to remotely access/monitor/control the system.

Honeywell-app.jpgJust like the RTH9580's onscreen interface, the iOS app has a clean, simple layout that tells you the current indoor temperature and humidity, as well as the outdoor temperature and humidity--with the ability to quickly pull up the five-day weather forecast for your location. You can easily set/adjust the daily/weekly schedule directly via the app, and a feature that's "coming soon" allows you to arrange a service call from a local HVAC contractor right from the app.

Beyond its Wi-Fi remote access feature, the RTH9580 offers a 7-day programmable schedule, with the option to set two or four events each day. The schedule is set by default to Energy Saver settings designed to reduce your heating/cooling costs, although you can easily change these settings to any numbers you want. You can also preset a vacation mode to override the schedule. Regarding the fan, the thermostat includes options for always on, auto (runs only when the heating/cooling system runs), and a nice circulate feature that runs the fan about 35 percent of the time. The RTH9580 lacks the auto sensors found in products like the Nest and Honeywell's own Lyric thermostat, but it does include Smart Response technology designed to help the thermostat learn how long it takes your home to reach a certain temperature and adjust its on/off times accordingly.

Other perks include the RTH9580's built-in humidity sensor to monitor your indoor humidity and the ability, through the web portal, to designate notification alerts regarding extreme changes in your home's temperature or humidity, the need for filter replacement, and more.

High Points
• The RTH9580 was very easy to install and add to my home network.
• The screen layouts for the thermostat, web portal, and iOS app are all clean and easy to navigate.
• I did not experience any connection problems when trying to control the RTH9580 via the app or web portal. Within the home, changes took effect within five to 10 seconds.
• The RTH9580 offers a 7-day programmable schedule with up to four events per day and is preset to reduce energy costs. You can change the schedule manually; or, you can answer general questions, and the system will configure itself accordingly.
• Honeywell's Wi-Fi thermostats can be integrated into other control platforms. In my case, I used it within the Logitech Harmony Home Control system and also within the Lutron "MyHome" app.

Low Points
• During the winter months, my review sample rebooted a lot--almost every day in the morning and sometimes more often than that. My online research revealed other users having this same problem specifically with the heating function, possibly because they aren't getting a stable 24 volts to keep the thermostat powered. After I switched over to the cooling system in warmer months, I did not experience any reboots.
• The RTH9580 has a fairly traditional aesthetic. It lacks the cool look of the Nest thermostat or even Honeywell's Lyric Wi-Fi thermostat.
• The RTH9580 requires a C wire for power, so it is not compatible with all systems.
• This system does not provide the energy-saving feedback that you can get with other smart products.

Comparison and Competition
The biggest name in smart thermostats right now is Nest, and the Nest thermostat carries a higher price tag of $249. The Nest model is a bit more plug-and-play than the Honeywell mode, with more emphasis on learning your habits to set up a schedule and using sensors to automatically make adjustments. It also provides feedback cues when you're saving energy.

Other competitors to the Honeywell RTH9580 includes the Ecobee3 ($249), the Allure Energy EverSense ($299), the LockState lineup, and Honeywell's own Lyric ($249) and other Wi-Fi Smart Thermostat models.

The Honeywell RTH9580 Wi-Fi Thermostat combines the look and programming functionality of a more traditional thermostat with some of the smart, networkable features that are gaining in popularity. It doesn't quite have the smarts and cool factor of pricier designs to learn your habits and sense your movements, but the RTH9580 is still very easy to set up, easy to use, and easy to monitor remotely through both the web portal and mobile app. Best of all, it can be easily integrated into a number of whole-house control systems. So far, beyond the unexplained morning reboots, I've been thoroughly pleased with the RTH9580's performance; it delivers all the features and control options I need in an attractive form.

Additional Resources
• Check out our Remotes & Control Systems category page for similar reviews.

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