RTH9585WF vs RTH9580WF: Buy the RTH9585WF

Want to buy a new Honeywell thermostat but you can decide decide between the RTH9585WF and the RTH9580WF?

Take it from me, buy the RTH9585WF!

These two thermostats are identical twins, born four years apart.

And since the 9585WF is the newer model, you will be better off  buying that one.

In the chart below, I have “compared” the main features of both thermostats.

(1) Main Features

[amazon table=”7080″]

Let’s be clear.

It would be easy to criticise these two thermostats for their dated and clumsy design.

After all, these aren’t going to challenge an Ecobee or a Nest in a beauty contest.

They may not be great looking thermostats but they are great thermostats.

Read on to find out why.

(2) HVAC Compatibility

Both of these thermostats work with 24V HVAC systems.

The thermostats will work on gas, electric, oil and duel fuel systems.

They work with multiple stage heating systems.

Used with conventional systems, they will work with 2 stages of cooling and 2 stages of heating.

However if they are connected to a system that is powered by a heat pump, the thermostats will work with 3 stages of heating and 2 of cooling.

Both thermostats will work with HVAC add ons such as humidifiers and dehumidifiers.

(3) Programming and Scheduling

The RTH9585WF and the RTH9580WF offer two options for scheduling.

Either you can leave the preset schedule to run or you can manually create your own.

You can create your own schedule with up to four “periods” per day.

Those four periods are; wake, leave, return and sleep and I will talk about these more later.

There seems to be a little confusion with its “smart response” learning.

This function is not the auto learning function of the Nest thermostat (that will create a schedule automatically by remembering your favourite temperatures at certain times of the day)

Smart Response is when the thermostat learns the speed with which your system heats or cools your home and delivers the right temperature at the right time.

So for instance, if in your schedule you want the temperature at 72 °F at 7.30am, then your thermostat knows the exact time to start your HVAC system in order that at 7.30am the temperature is 72 °F.

You can programme these schedules on the thermostats themselves, via the Honeywell Total Comfort app or via your Honeywell account online.

And the process is easy, which ever device you do it from.

In the scheduling tab, there is a grid that has each day of the week going down the screen and the 4 periods (wake, leave return and sleep) going across the screen.

Changing the schedule is as simple as clicking on one of the periods of one of the days.

You can then set a “wake” time and set a minimum temperature (at which point your heating will turn on) or a maximum temperatures (at which point your cooling system will start.)

(4) Screen Details

The screens on these two thermostats are color and they are touch screen.

They are approximately 4.5″ diagonally in size.

The screen is large enough to display the most important details, which includes;

  • time & date
  • outside temperature and humidity
  • indoor temperature and humidity
  • set point temperature adjuster.

You can change the background color on the screen to any that you want.

It might be that one particular color suits your room more.

Or if you have a visual impairment then you might see certain colors a lot more clearly than others.

The screen can also be locked so that only authorised people can access the device and change the settings.

(5) Smart Heating Features

There are three smart heating features that these two Honeywell thermostats don’t have that other smart thermostats do have:

  • room sensors
  • geofencing
  • energy reporting

However, like all wi-fi thermostats, these two models can save you money.

Find out how much money you could save by installing a Honeywell thermostat.

(6) Remote Access

These two thermostats can both be controlled via apps for your favourite smart phones and tablets and via a browser on your laptop or desktop PC.

In order  to run the app on your iPhone or iPad, you will need to be running iOS version 9 or later.

In order to run the app on your favourite Android device, it will need to be running version 4 or later.

In a later section, I describe the Honeywell Total Comfort App in much more detail.

(7) Connection, Power and Warranty

These Honeywell thermostats both connect directly to your 2.4 Ghz Wi-Fi router.

You don’t need to connect to a smart hub such as SmartThings but if you did it would allow you to do more.

The thermostats need to powered by a “c” wire. They are not battery powered.

Both of these wi-fi thermostats have a 1 year limited warranty on them.

(8) Honeywell Total Comfort App

The same app is used by both thermostats.

It is a powerful but easy to use app that runs very reliably.

You can set and manage multiple Honeywell thermostats within the app.

The main features of the app are;

  • changing temperature
  • change the schedule
  • view the weather forecast

The video below highlights the main features of the app very well.

(9) Installation

The video above takes you through, step by step, the 13 steps that are needed to uninstall your existing thermostat and installing any Honeywell thermostat.

And those steps are;

  1. Switch off the power to your heating and cooling system from your circuit breaker box.
  2. Remove the front of your old thermostat but keep the wall plate attached.
  3. Before you do anything else, take a photo of your wires.
  4. Check to see if you have any “jumper” wires.
  5. Attach the wire labels, that came in the box with the thermostat, to the wires on your system.
  6. Use a screwdriver to loosen and disconnect the wires.
  7. Remove the old wall plate but be careful to ensure that the wires don’t disappear into the wall.
  8. Center your new thermostat on the wall, make sure it is level and mark the position of the pilot holes.
  9. Drill the pilot holes and tap the wall anchors in with a hammer.
  10. Hold the wall plate on the wall and attach the screws.
  11. Connect the wires into the terminals
  12. Attach the new thermostat to the wall plate.
  13. Switch the power to your heating and cooling system back on.

You are now ready to set up your thermostat.

(10) Set Up

Once one of the RTH thermostats is installed, there are two stages of set up.

  1. Enrollment: which includes connecting your thermostat to your wi-fi network.
  2. Registration: in which you create an online account for remote access.


Before you start, make sure that you;

  • you know the name and the password of your home wi-fi
  • have a laptop, smart phone or tablet that is already connected to your wi-fi
  • have your thermostat I.D. card
  • quick start guide
  1. Make sure that your thermostat is on the wi-fi set up page
  2. On your laptop, phone or tablet in your wi-fi settings, select the wi-fi named “Thermostat 1234”.
  3. On the same device open a browser- it should open on a Honeywell wi-fi set up page.
  4. If it doesn’t, type in “” into your address bar.
  5. Find and select the name of your home wi-fi.
  6. Now enter your wi-fi password.
  7. Your thermostat should should display a message, “Connection Successful”.
  8. A MAC ID will be displayed.

You will need this for the next stage, Wi-Fi thermostat registration


(11) Problems and Troubleshooting

One of the most common problems about thermostats is that people can’t find their copy of the user manual.

This page has the user manual for the rth8589WF in several different languages.

The main problems that these two models of thermostats seem to suffer from is that lots of people have a very bad experience with Honeywell customer services!

Some people struggle to get through to talk to someone human or to get them to listen to what a problem really is instead of just reading from a script.

Other people complain that Honeywell have refused to send them a replacement thermostat when theirs is broken.

Another issue that a few people have raised, is that the RTH9580 will randomly lose wi-fi connection and it will not re connect.

However, if you have any problems, then there is a very detailed section of the Honeywell website that you should visit here.

(12) Pros, Cons & Verdict

Because these two thermostats are essentially exactly the same in terms of how they look and function you should only consider buying the newest model the RTH9585WF because as it will be supported by Honeywell for longer.

[amazon table=”7094″]