Looking for energy monitoring variable fan switch

I have a radon fan (draws about 1A) that I currently have plugged into a Zooz ZEN15 in order to monitor energy usage. It came into service this past December. Now that we've had a few warm days this year, I am seeing from the graph that my dehumidifier in my sealed crawl space (also on a ZEN15) is consuming 2-3 times the energy than it did at the hottest times last summer. See below. The radon fan pulls from underneath the barrier, but obviously it is also pulling in warm, moist area from outside that then must be dehumidified.

I'd like to put the fan on a variable speed fan switch and experiment with running it at lower CFM on warmer days. But I'd also like to continue to monitor the energy the fan uses. Is there a fan switch (preferably Z-Wave+) that also does energy monitoring? I'm familiar with the GE/Jasco fan switch, but would like to have the energy monitoring function there as well.

So you're thinking the Radon fan is causing leakage of makeup air into the crawl space because it's creating negative pressure below the crawl space? This results in an increase of Humid air from outside collecting in the crawl space...


My radon fan is on a Qubino relay, which measures power, and can be installed in the switch box. So...if you found a fan switch that handled the variable speed part, you could put the Quibino in front of it, and just use it for power monitoring.


Darn it!! Scott just beat me to it. I was going to say you could use any power monitoring switch in front of the fan control and get both.

However, I do have to ask, how much power does your Radon fan use a month? Is it going to cost more to get the hardware to do this than it is to run the fan?

Fair question. When run at full speed, the radon fan consumes 3.4 kwh/day. The purpose of the power monitoring isn't related to energy consumption obviously, since it is a constant. The purpose of the energy monitoring is to detect if the fan is supposed to be on, but isn't. Not likely, but it could happen and I'd want to alert on that.

I'm realizing that the power monitoring isn't a must have, but since I'm going to be buying a smart fan switch anyway, I was hoping to find all-in-one. I also posted as a case of how useful this hobby can be .. the power monitoring on the dehumidifier let me know there was an issue.

Failure of the fan happens. Mine lasted about 10 years (5 over MTBF), and I didn't notice it for quite some time. I installed the Qubino for exactly this purpose (Power Monitoring), and I have a RM4 Rule which lets me know if the power drops below a certain threshold.

I did the same thing you're doing for the Dehumidifier (Power monitoring). I didn't mess with the fan speed though. I have a lighted Dumb Switch so I have a visual indicator that power is getting to the fan, and behind that is the Qubino.

Good luck!

Putting aside the desire to energy monitor (I will probably add Quibino as suggested later), I find now disappointment in my choice of Z-Wave Fan Control to control the speed of the radon fan. I got the Honeywell one made by Jasco which was $10 cheaper than the GE Enbrighten brand but the same thing.

I knew going in that the fan only gave you Low/Medium/High speed, but what I didn't expect was that Medium and Low are half and quarter speed. There is no 75% speed (i.e. 75 and 100 are the same level). For my radon fan, high speed gets me pressure of 1.6, while medium and low give me pressure of 0.4 and 0.3 respectively. I need to be able to drop it to about 1.0.

Are there still no smart fan controls with continuously variable speed? I found Z-Wave device for TRUE variable speed fan control? - Devices & Integrations - SmartThings Community. I don't understand why having a variable speed smart switch is hard to do. There are continuously variable dumb fan controls such as this one.

Unrelated to the above and this is really a question about energy monitoring with a ZEN15. If a device is drawing 0.506A at 127.674V, why wouldn't that be 64W?

Interesting. I just looked at one of my Zooz Power switches, and it's doing some of the same fuzzy math.

I expect it's something to do with averaging,,or instantaneous measurements, but it certainly seems to be doing poor arithmetic!


Shamelessly bumping my own thread in hopes some new eyes might have new ideas. Dropping the energy monitoring nice to have, what I am looking for is a way to control a fan (inductive load) that will at least give me off, full, or reduced speed where reduced speed means one speed I select that is probably around 70%. Load is about 2A.

Jasco/GE/Honeywell fan switches won't work because they are preset to 25%/50%/100% and cannot (as far as I know) be changed.

At the moment, I am using a P&S Full Range Multiple Ceiling Fan Speed Control 6A 94601-IV which gives me full range, but no ability to automate. One thing I was thinking is if I had a smart switch that would bypass the speed control. That is, I would leave the speed control at the desire reduced speed, but use the smart switch to bypass it to full. Easy enough to wire, but I probably would damage the P&S control by presenting hot on its load side. To achieve what I want, I'd probably need a smart SPDT relay that can handle the load and be Hubitat controlled. But it would need to be "break before make".

Any brilliant solutions? I'm up to crazy ideas. Within reason, cost is not a constraint. Physical space for switches/devices is also not a constraint as this is in a storage room.

Large variety of DOB,DOM Time delays.
Often available at HVAC or plumbing supply houses near you.
ICM104 at first glance.

Not smart but has potential to integrate with one that is.