Unexpected Non-Detection: Exhaust Fans


So, I’ve had Sense for 9 months. 29 devices detected. Sense has been very impressive in my house. It’s found many devices that I did not expect it to.

It got me thinking though…are there any devices that I’m surprised that it hasn’t found yet?

Bathroom exhaust fans.

I have three bathrooms, each with an exhaust fan. Two are similar fans and an the basement one is different.

Sense hasn’t detected these fans. They are used frequently (multiple times daily).

Has anyone had their bathroom exhaust fans found by Sense? I wonder why Sense has an issue with this type of equipment. Sense quickly found me furnace and water heater exhaust blowers.


I have 27 detections in 2 months but not a single fan. I also have the bathroom fans, ceiling fans, oven, stovetop, air handler and heat pump fan. For some reason Sense has not detected any. I would like to know likely causes as to why certain types of devices are not detected in a home.


I wondered the same thing. When I asked about a list of items I was told that items under 35 watts would not likely be found. I’m 3 months in and the fans have not been found even though they consume 60 watts. I was really hoping that my gas furnace would have been found, especially after this cold winter. I was also told that ecm motors are hard for sense to find due to the irregular patterns.

Did sense find most of your 29 items right away? I’m at 10 after 3 months.


There was a blitz of items in the first few months for items such a Fridge, Freezer, Garage Door Opener that cycle multiple times daily. But there was a steady stream of items being found during month 4 through 8. Some items couldn’t be found until winter hit and my furnace and heaters began to run.

Sense even found one 10W LED bulb in a storage room with a pull cord switch. It’s a super sluthe detective. Doesn’t miss much.

Sense is basically finding everything except my Always On devices (as expected), my single CFL/LED light bulb fixtures, dimmer switch lights, small electronics, laptops, and kitchen applicances that we haven’t used enough yet such as the blender or crock pot. I understand why Sense hasn’t picked up on this list of items based on the excellent Web Articles from Sense.

The bathroom exhaust fans are the only item in the house that I was surprised that it hasn’t found. They are simple motors and cycled daily. I have one old fan, one replacement fan, and one new fan. So it’s a decent sample group.

We just got a new vacuum. My wife was happy about the new vacuum. I’m just excited for the day that Sense will detect it. I know it will. It’s been awhile since I’ve had a new device found since it’s found everything.

1 Like

Do the bathroom fans also have ballasted florescent fixtures. Mine do. None of my 4 bathroom fans have been found, but I’m thinking that the ballast might throw off the typical motor signature.


I have two bathroom fans and only one has been detected and it always shows up accurately on sense but the other one hasn’t been detected yet


@kevin1 Good question. The fans are indepentdant devices. So, no lights attached.

I have a light fixture above the vanity on a separate switch. Each of the bathroom lights have been found by Sense.


@mike_gessner that is great to hear that one fan has been found by your Sense. I have hope now! I was hoping that someone on the forum had one of theirs detected. I’ll continue to wait on that note.


I too am surprised that the bath fans haven’t been detected. I have 3, and they cycle more times in a day than I care to admit. No light on any of them, just motor.

At this point, I’d settle for my fridge being detected.


It’s been unpredictable with detections. I had several in the first few days, usually 2 at a time. I would then go a week without any followed by a couple at a time several days a week. I have had as many as 4 detections a day, it’s happened twice now. I would guess the longest stretch without detections has been a week. I’ve also had it work the opposite where sense has deleted or removed 4 detections in a day. I’ve lost about a dozen total. It’s not just sense that has removed them as I have deleted a few. They say if I’ve renamed them then that doesn’t happen but I’m not totally convinced because I usually rename each one as soon as I see it. There is somewhat of a system I follow when I get a detection and I’m in the process of identifying or confirming a device.
A lot of the most recent ones have not been identified and don’t have any or much history. I’m sure I’ll have to delete a few. I’m afraid that if I don’t delete them that the data is attached somewhere and not freed up to get a proper detection. Of course that’s just a guess because the whole process is pretty tight lipped.
I have one device I’d really like to be detected. I would trade ten of mine for this one but I’m afraid it’s not going to happen. It’s a 500 watt heating element so I have no idea what the difficulty is.


There’s a couple challenges here. (1) Most bathroom exhaust fans are pretty low wattage, compared to something like an HVAC fan. Last time I checked, I think mine was only about 50W. (2) They’re used pretty irregularly, though this shouldn’t matter too much, and (3) They often coincide pretty much exactly with other devices turning on, like multiple lights. That last one can make things especially tricky, and even more so if those concurrent devices are pulling similar wattage like incandescents.


I have two bathroom fans (well, more than that but only two that get used). One of them has been detected and is pretty reliable. The other is used almost as much, if not more, but it has not been detected at all.


@RyanAtSense, Thank you for the detailed response. Since Sense has identified a single 10W Phillips LED Bulb in my house, I have high expectations of Sense’s capabilities…maybe unrealistically high.

It’s useful to know that 50W is actually considered low; this will help to set the bar for my expectations on other devices. Looking closer at the bathroom fan profile, it is only about 40W and doesn’t even have a large inrush spike that other identified motors have. So, this is becoming more reasonable.

And that is a very good point about coinciding with other devices such as the lights. Even though the fan and lights are on separate switches, the occupants would normally hit both rocker switches at a similar moment when hit the switches.

Now, you’re going to condition me to hit one switch at a time with a relaxed pause in between. Sometimes it’s a good idea to slow down in life, right?

1 Like

Keep in mind that wattage is only a single factor in detection. True, it’s a major one, but there are a lot of other factors at play. I wouldn’t see too many expectations around just high/low wattage numbers, are there’s some high-wattage devices that can be tough to detect (and low-wattage devices that are easy to detect).

But glad we can help bring some moments of mindfulness to your life. Maybe we should add some guided breathing exercises to the app :grin:

1 Like