Power usage split in half?


#1

I’m noticing a trend with several of my big appliances. Once Sense detects a large appliance, let’s say my water heater, it is only showing half of the wattage it uses under the appliance name. The other half of it’s usage is still listed under “other.” I first noticed it with the water heater, but it also does it with the central heater and the HVAC fan. But why??

I’ve come up with 2 theories, not sure if either one is correct. (A) Since these are double pole breaker devices, sense has only detected the device on one phase. If that’s the case, it’ll eventually find it on the other phase and then I can merge the 2. But, shouldn’t the power usage look identical on the 2 phases, making device detection super simple on the second phase? (B) Since the water heater has 2 heating elements, what I am seeing as my water heater is just one element, and the other element hasn’t been discovered yet. But, if that’s the case, why would my central heat and HVAC fan also be splitting in half??

Any ideas?


#2

Most electric water heaters are wired so that only one element comes on at a time so your option B doesnt make sense. But some are wired where both elements are on simultaneously so it cant be ruled out entirely.

Option A is true only if there is no noise on the undetected phase, i.e., the signal is identical on both phases. I would bet this isnt the case. There’s one phase with more noise on it that’s making detection more difficult on that phase.

Give it time. It should get better at detecting both phases but I have to admit, after a year, mine still only detects one phase of my heater at a rate far higher than I would like.


#3

I’m having the same issue. It is very frustrating.


#4

It’s a long known problem with 240v appliances. If you search the forum you’ll find plenty of posts.


#5

Try checking that the Sense current sensor clamps are fully closed in your breaker panel. If one of the clamps is partially open even a small amount, then the current on that phase won’t get measured.