I have a nest thermostat that I'm considering replacing after this whole Nest API fiasco. I also have a furnace humidifier that controls humidity in the whole house but I don't have enough wires run up to the thermostat to control it from the thermostat and I'm not able to pull new wires due to a drywall ceiling in the basement. It's controlled by an analog dial based humidistat at the furnace.
Does anyone know how I could integrate the humidifier into a thermostat without the extra wires up to it? Perhaps just a second thermostat at the furnace that only controls humidity?
Edit to add more detail: the analog dial based humidistat at the furnace doesn't actually monitor humidty, it just sets how much moisture is added when heat cycle runs. What I'm looking to do is have a thermostat or some other humidity sensor monitor the actual humidity and adjust accordingly.
If the analog dial is anything like mine, it doesn't control the amount of moisture. The humidistat just controls the on/off of the water valve. When the humidity level at the humidistat is satisfied, the water valve won't open. As soon as the humidity level falls, the next time the furnace fires up, the humidistat triggers the valve to open.
To have some automated control of this you will need to remove the analog dial and use some other device to control the water valve. Arduino and relay??? You would also need something to measure humidity but it should be fairly easily doable.
Hmm interesting, this could be more complicated than I though. The dial on mine seems to adjust for amount of moisture as there is a little graphic that shows little moisture at the far left and more moisture at the far right. I'll have to take a closer look at it!
All a humidistat does is send 24VAC to a solenoid on the humidifier. The humidistat senses humidity, and either does or does not energize the solenoid.
If I were going to do this with Hubitat, I would use a Zigbee or Z-wave outlet, 24VAC furnace transformer, and use that to turn on the humidifier. It is just a two wire connection at the solenoid, so it is very easy to wire up. You could use various humidity sensors around the house, and build rules around humidity levels.
There are rules of thumb about how much humidity you want or need based upon outdoor temperature. Many humidistats or better thermostats take outdoor air temp into account to you don't get drippy windows and therefore mold or rot.
I use one of these to change the 4 wires run for my thermostat into a 5 wire system to support smart thermostats requiring constant power. If you currently have 5 and need to expand to 6, this would also work. The only thing you can't use this for is the C wire.
The documentation on the Venstar website is great and it's super easy to install.
Interesting! This would definitely work for my Nest thermostat but I would like to get away from the Nest, I'll have to see if there is something zigbee or zwave that can also do humidity!
I'm in a similar situation as the OP but I'm starting by replacing a "dumb" thermostat. It currently only has 4 wires running to it (no C wire). I'd like to add either a smart thermostat or at least one controllable by HE. I too would like to have the humidifier controlled more intelligently. The thermostats I've looked at such as Ecobees require ACC wires.
Has anyone done what @neonturbo suggested? I've already got Zooz 4-in-1's all around my house for humidity readings. I could use that Averaging app to pool them. What kind of thermostat would be best for something like this? I'd need one I could get fairly quick updates from to know when to turn on the solenoid through HE.
I'm guessing not but thought I'd ask: Some thermostats, such as Ecobee, come with a wire adapter to add a C wire. Could you use this Add-A Wire with that to then add an ACC wire? So go from a 4-wire to a 6-wire?
You can use the Venestar Add-A-Wire device for any thermostat because it comes with the box that goes in your Furnace and the diode wires that go near your thermostat. The Eccobbee PEK device works for Ecobee devices because the diode is built into the backplate of the thermostat. You can't use the PEK on any other thermostat. Also, with the Venestar, there are only certain wires that you can use it on. For example, you cannot use it for the C-Wire. You can go from 4 to 5 or from 5 to 6. but I don't believe you can go from 4 to 6. That would require re-wiring. But give them a shout, maybe they have something that can help you.
Wow! Very nifty but VERY expensive! Depending on how far your furnace is from your thermostat, it might be easier to just pull new wire. I don't know how much electricians cost where you're located but unless you have a very complicated house I can't imagine running a new wire would cost anywhere near $180. Before going through this trouble, make sure that you find a thermostat that you're sure is going to work to control the humidifier though. Not many do from what I've been able to find.
I never heard back from Venestar folks. So I went ahead with the Fast-Stat.
The 3000 model I ordered was just over $100. Still expensive. But yes, the thermostat I have is a good distance from my furnace and a floor above it. The entire basement is finished with drywall ceilings. It would have difficult and expensive to run new wire. I considered installing the thermostat in a new location, but there really weren't any better ones.
I decided to go with an Ecobee thermostat. It definitely controls the humidifier (can be wired single or with 2 wires) and I found many diagrams for wiring it. The 3000 I ordered should give me what I need. I confirmed that with the manufacturer and by checking with the Ecobee folks. I wasn't thrilled about the cloud reliance, but the other models I looked at had limitations or just wouldn't do what I needed. Time will tell I guess.
I'm also wondering if anyone has rigged up non-thermostat control of a bypass humidifier as @neonturbo described. I sold my Nest and replaced it with a GoControl. There's no humidifier control on the GoControl. However, my humidifier was never actually being controlled by the thermostat in the first place. Instead, I have a manual dial that looks like this:
The humidifier is already connected to the furnace and automatically comes on with the heat. Am I correct that in order to integrate this with Hubitat I would not use this dial at all, and instead replace it with a Zigbee/Z-Wave outlet?
Same deal as described above. That dial (a humidistat) is just closing contacts when the humidity is low and opening them when humidity reaches the desired value.
Two ways to address this.
If the transformer for the humidifier is accessible, you can just set that dial to full ON and then use a smart switch to turn the mains power on and off to the humidifier based on humidity level from a hygrometer paired to HE and the ON state of your furnace.
If the transformer is not accessible, remove that humidistat or find where it's wire attach to the furnace and then use a Qubino or other low voltage dry contact relay to close the circuit, thus sending power to the humidifier's water valve based on humidity level from a hygrometer paired to HE and the ON state of your furnace.
I should be obvious that you want you rule to know the state of the furnace, and only supply power to the humidifiers water valve when the humidity is below you set point AND the furnace is running.
What I ended up doing was replacing my older humidistat with one of these:
I wanted some control based on the outside temperature, which this supports. However, I did not have a high-efficiency furnace with outside air intake, so I was always concerned that I would not have any way to get the outdoor temperature probe out there.
But, I found that I had no use for the analog telephone line running into the house, and the box on the outside of the wall already had wiring coming into the house from outside. I was able to wire the temperature probe to the phone wiring on the outside of the house, and run a 2-wire thermostat wire from the entry point in the basement, over to the furnace.
Once the rewiring was done, it seems to be working well. My humidity level tracks with the outdoor temperature of the outdoor probe, and I've noticed much less condensation on my windows last winter.
And as a side note, I do currently have a venstar add-a-wire on my furnace to provide a (5th?) wire to my z-wave thermostat, as the old one was an un-powered dumb thermostat. It's been working very well for the past 4 years.
Let me know if you'd like further information on my setup...
Edit: This humidistat has the "Blower Activation" feature, which will run the furnace fan periodically if the heat has not run, to monitor and adjust the humidity in between heat runs.
Thanks, this might be the way to go, at least until there is a smart humidistat. Good thinking with the phone line. That might work for me. I ripped out a lot, but I didn't remove the part that goes outside.
Honestly I don't know if my little bypass humidifier even works very well. It's a Clean Comfort HE17, which I think is made by Goodman. I change the vapor pad each year and it definitely moves water. Maybe some active control with a humidistat would help things, but I've never had condensation on windows, for instance, with it on full blast. It'd be nice to be able to monitor some numbers to really verify what it's doing.
yes, and the display on my new humidistat seems to agree with the readings from my thermostat and various wireless tag sensors, so I think its being pretty accurate.
