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Sunday, September 12, 2021

Peak power pricing: Sensibo heat pump controller

Last winter I was part of a pilot project with Hydro Quebec to manage my power consumption according to demand. (Details can be found by clicking here, and early results here.) Net result? About a $400 saving over the winter. 

So far so good. And last winter, much of it spent in some form of lockdown, meant I was always home at 05:55 to get up and pad around turning thermostats down. Next step is to automate the process so I can sleep in, or travel. Turns out Hydro is working on this, with their HiLo subsidiary offering smart thermostats for baseboard heaters. But there are a few problems with their approach so far. 

First, these are controlled through Hydro's servers talking to the thermostats via my router. Google Home will also do this; but I recall a server problem at Google a while back that left people unable to even turn on a light. So keeping local control is a better idea in my view.

Second, at this point their equipment will only control baseboards. I've got one baseboard that needs controlling; otherwise, I've got a heat pump, two heated floors and two convection units with built-in thermostats. So that doesn't do me much good even if I were willing to accept Hydro reaching into my home network and fiddling with stuff. 

Separately I discovered a type of gizmo for controlling any heat pump or air conditioner that has a remote control. This is a bit like the universal remote you used to be able to buy to replace the remotes for the TV, set-top box, PCR, VCR, tape deck and DVD player (ask your Dad). Two looked interesting: the Sensibo and the Cielo (for reviews, click here). On the face of it the Cielo has more features (including a display), but ultimately I ordered the Sensibo from Home Depot, on the basis that I can just take it back to the store if there is a problem. At $129.99 Canadian before sales tax, it was a bit more than the US price, which did not include shipping to Canada. (It is interesting to note that the black one was $179.99. Not sure what that is about.)


Photos show what is in the box: the device, a 110V adapter and a USB cable. There is a second proprietary port on the underside of the device, but with no indication of what this might be for. 

The instructions in the box are terse, verging on non-existent. The manual is not easily found on the Sensibo website, but I found it on Lowe's site (click here). The main installation step, which was minor, was installing the app (available for iOS and Android, but not PC) and connecting it to my WiFi system. Then you point your existing heat pump remote at it and press On a couple of times. After that it is entirely run from my phone. 

The scheduling function has a seven-day calendar that repeats. I discovered that if you try to schedule stuff with the heat pump off, all you can do is turn it on or off; the heat pump will start up with the last settings active. But if the heat pump is on, you can program all the functions: mode, temperature, fan speed and vane orientation, etc. So far all very neat.

A couple of downsides. Unlike the remote, which takes a couple of AA batteries, it needs the 110V connection. This sort of limits where you can put it, which is further limited by the fact that, like the remote, it needs line of sight to the heat pump to work. Photos show a jury-rigged set up, with the gizmo plugged into the 110 outlet on the stove; I have since plugged it into the outlet for the microwave, which involved drilling some holes in the cabinetry.

Powering it off and back on seems to bring it back to where you set it, so that is fine. 

Finally I didn't think I could control it from beyond the range of my WiFi system. But initial tests made by walking up the street until my phone was no longer connected to my WiFi imply that I can control it at a distance; this means that my phone talks to my router over cell networks. (I turned the phone off before coming back home, to be sure it really was talking over the cell network). It turns out that the app and the device talk to one another through a cloud-based server of some sort, and do not communicate directly. The Cielo system is apparently similar. Oh well. Hopefully this system will still be live in a year or a decade. I still have the remote and a stash of AA batteries, so there is a backup plan. But the lack of clarity around this in the Sensibo advertising material and installation manuals is disappointing.

So I am getting ready for next winter, hoping that I will be able to go away for a while and just leave a program running that will dial back twice a day, even if Hydro isn't asking for it. The only real issue is a I have a single convection heater with integrated thermostat and a second baseboard heater that really need to be adjusted manually, especially if the temperatures are low enough that the heat pump is no longer effective. (The coldest it got at the beginning of Hydro events last winter was -17C, which, as we all know, is relatively balmy for this part of the world.) I can set these to a low temperature before going away, but will still have to get up at the crack of dawn to adjust them if I am home. So while not a complete solution, progress is being made. Stay tuned for updates.

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