Impact of better thermostats!

After Sense detected my AC, I noticed it short cycling. My thermostats (3 zones) had a non-adjustable swing differential of 0.5 degrees (e.g., if I set it to 75, it would turn on when it hit 75.25 and off when it hit 74.75). I immediately purchased new thermostats where I set the swing differential at 2 degrees. Check out the difference!

36 hours with old thermostats (High on Monday was 97, High on Tuesday was 87):

36 hours with new thermostats (High on Sunday was 90, high on Monday is 91):

I now have fewer cycles and longer breaks between start-ups, which should help my system last much longer. I also have much longer run times, which should let it run more efficiently, and has helped significantly with indoor humidity (my portable dehumidifiers are running much less).



I suppose it might be hard to simply compare overall energy use pre & post because of weather variation but that would be cool to evaluate. Would love a swing differential vs. cycling vs. energy chart!

I also wonder about Sense’s accuracy in capturing every cycle: What I have noticed on my window AC is that frequent cycling is captured more precisely by Sense (the compressor at least); infrequent cycling is significantly more error-prone in my case. I can verify this because I have a ground-truth smartplug on the unit.

@kevin1 also just went deep on a not-necessarily-unrelated topic.

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You are right about sense inconsistently capturing a cycle. I initially wanted 1 picture with an immediate before/after the installation of the thermostats with swing differential, but Sense was really bad at picking up the AC right after the change. I chose the time-frame in the picture because it seemed to have fewer misses; it only seemed to miss one (maybe 2) cycle(s) that I noticed (based on the overall net metering chart). Unfortunately, since my dehumidifier runs a lot less now, Sense almost never captures it :frowning:

Which thermostat did you use? I’ve always been confused why more basic programmable thermostats don’t have at least the option for a full one- or two-degree deadband in addition to the “stock” 0.5 degree setting. Just that one option can have a dramatic impact on operation.

Also, do you have a dedicated zone controller? I’ve been researching one for my home and am interested in what others are using.

I bought Lux thermostats. They were the least expensive I could find that had adjustable swing, good reviews, and were programmable. This is what I bought. Each zone in my house operates independently.