Duplicate HVAC fan device detected. This was new for me



As some of you know I have been struggling with our two AC system components being detected. They’re similarly sized systems installed in spring of 2016 using components from the same manufacturer.

A couple days ago a new Heat 7 was detected. The suggested community name was HVAC Fan. This on its own was interesting as both of our 220V air handlers are already represented within Sense. I then thought maybe Sense had found the other phase of one them since the app doesn’t tell us what legs the devices are pulling from. If you’re wondering why our AC fans are running almost in November in New England, we run the fans for ~5-10 minutes per hour to circulate the air in the home. Our heat source is forced hot water radiators so the air ducts aren’t for used for heating.

I enabled on/off notifications for the new device and our existing fan devices to see if a pattern emerged. I was able to see this new Heat 7 was turning on/off at the very same time as our existing upstairs fan device. That behavior further lead me to think it was the other half of the 220V air handler, and the 340W the existing fan device had been reporting up until this point was only one half of its actual usage.

I nearly merged the devices, but out of caution I opened a case to ask if support could confirm my suspicions of this being the other half of a 220V device.

I was surprised when they came back and said this new Heat 7 was a duplicate of our existing upstairs air handler device, and the existing device was already reporting usage on each phase. The recommendation was to delete the newly detected device.

I’m glad support was able to quickly provide feedback, but had I gone on assumption and merged the devices would I basically have been double-counting usage or would it have someone worked that out and still only counted 340W? I’m also a bit confused as to how a new device was detected. If the home’s usage wasn’t going up (or down) by an extra value of ~340W in this case, then what was it attributing this to?