z-wave based humidity control? HRV or dehumidifier

Hello all,

Has anyone worked out a z wave based humidity control solution? I have an HRV and would like to control it with the dehumidifier contacts on a z-wave thermostat. The only z-wave thermostat I can find that can run a dehumidifier or HRV is the Radio Thermostats CT-80 with a z-wave USNAP module in total costing $218. I had a CT-30 thermostat and replaced it because it would freeze my entire zwave network (an acknowledged problem by the makers) when it was connected to AC. I moved to a Trane z-wave thermostat only to find out it wont go below 55F. I dont want to buy another thermostat, especially an expensive one only to find out it also is not good or that their is a better solution to control my HRV. Any ideas?

Don’t do it! At least, not yet. I purchased a CT80 that came with a WIFI module and added a USNAP Z-wave module fw v7.4 for redundancy. I assumed that the Radio Thermostat published “workaround” would work for the Z-wave problem until I realized that the CT80 doesn’t have any batteries. Radio Thermostat tech support was useless. I finally talked to a Z-wave manager. He advised that the new fw v9 USNAP module would work, that Homewerks had it now, and Radio Thermostat would have it at the beginning of the year. I tried to contact Homewerks, but they never responded. I’m waiting to see if Radio Thermostat offers it.

However, AFAIK, the Vera thermostat protocol doesn’t offer humidity control. There are Z-wave humidity sensors, but setting humidity on a thermostat is different. WIFI will hopefully be an option; there are Vera plug-ins for Radio Thermostat and Ecobee. I know that the Radio Thermostat plug-in doesn’t offer humidity settings, but don’t know about Ecobee. Radio Thermostat does offer a public API that exposes pretty much all of a thermostat’s capabilities. See this thread for more info.

Also, if you are interested in the CT80 and want to save money, consider the Current Innovations CI800. It is a Canadian version and sells for much less on ebay. It identifies itself as a CT80 Rev B2 V1.09.

Wow thanks for all the great information, that is a big help! I am disappointed to hear that they still dont make a z-wave USNAP worth a darn. The Current Innovations CI800 is crazy less expensive, thanks for pointing that out, what a great deal. Too bad I dont think I will be buying one. My hope had been to truly do everything over z-wave. I would rather not depend on a plugin. I am also surprised to hear Vera does not support humidity as part of the thermostat control that was my main reason for considering that solution.

I guess maybe I will just buy a ST814 - Wireless Temperature / Humidity Detector and a relay module and see if I can?t setup a scene to do what I want. I wonder if the Aeon labs all in one motion sensors detect humidity very accurately. Has anyone tried doing something like this?

If you’re talking about a Z-wave relay module, then I don’t know why your idea wouldn’t work.

KKL, were you even able to get a Z-Wave USNAP with v9 firmware? I’m still only seeing v7.4 on the market.

Or, are there any other Z-Wave thermostats with integrated humidity control on the market now?

Anyone know of a TStat that manages the Humidity, with a 2 Stg condenser that I can control the Temp via ZWave? I don’t care if I can’t manage Humidity via the APP, just so long as what I manually set the TStat to for humidity works. Temp and On/OFF is fine for now

I have been wanting to control my humidifier also. Here’s what I have to work with and hopefully it’s possible
Thermostat: Honeywell TH8320U1008
Humidifier: I forget the brand, but it’s a steam system that I bought off ebay.
i/o controller: Global Cache GC-100 with 3 sets of i/o ports

I think what I also need is a Zwave Humidity sensor

My idea is to use all of these items. Let me know if my idea wrong/bad/won’t work

The Humidifier has 4 wires coming off it. 2 of the wires go into the humidistat, once those two wires make a connection it tells the humidifier to turn on. The other 2 wires go to the furnace to turn the fan on.

My idea is to hook those 4 wires up to my GC-100 for control through my vera. Since vera should be able to control those ports it can control the humidifier. Then I can use a humidity sensor and my honeywell thermostat.

So once vera sees the humidity sensor go past a set number it will do two things.

  1. close the circuit for the two wires going to the humidifier that are for the humidistat and the humidifier will turn on.
  2. turn the fan on via the zwave thermostat

I also don’t know if I should hook the humidifier wires that are supposed to go to the furnace up to the GC-100 or should I put some something else in between those wires so the humidifier thinks it turns the furnace fan on. I tired to hook those wires up to my furnace to use it the way its supposed to work, but I could never have it turn just the fan on or not blow a fuse in the furnace.

Old post, but relevant update - the Radio Thermostat CT-80 with a current USNAP module now works with Z-Wave. Still no Z-Wave humidity control, but this is a Z-Wave thermostat that also controls a humidifier and lets you manually set the humidity. NOTE: the version B is a new hardware revision of the CT-80, so you must buy the current version - don’t buy from a 3rd party seller unless they can confirm it is a version B.

Just to be clear, the “current USNAP module” that works is FW9.0. Do not buy v7.4. Also, there seems to be an issue with the Z-wave module getting updated with the current temperature setpoint and fan setting, particularly if changed by the WIFI USNAP module. For example, currently my CT80 is set for 69 degrees and the fan on Cycle. Vera shows that correctly in the WIFI plug-in, but the Z-wave device shows the target as 67 degrees and the fan as Auto. Polling, reloading, or resetting of Vera makes no difference, nor does resetting or power cycling the CT80.