Our Sense home energy monitor saved our butts and our bucks.

Regular readers know I love data, especially my own health data. This post isn’t about health data, but it makes my favorite point: knowledge is power, and it’s empowering to know what’s going on. Am I right?

Last year we got a nifty thing for home energy management, and this summer it detected a small disaster in process that would have cost us hundreds of dollars. At the peak of AC season in July, this notification popped up on my phone one morning: my electricity consumption was FOUR TIMES normal:

As the saga unfolded in the coming days, at one point I called my electric company and asked if they could figure out what the problem was. They said they have no idea what’s going on inside my house – all they ever see is the meter, and they only see that when they take their monthly reading. So if I have an energy “leak,” nobody would know until the ginormous bill comes in. Not good.

The device we’d bought is the Sense home energy monitor. It’s not cheap: around $250, plus an electrician to install it, because it’s a serious physical thing that attaches to your electrical supply line (at the breaker box) and listens for patterns in the electrical current flowing through the mains.

From this, it detects the “fingerprint” of different devices in your home. (Who knew that fridges and heaters etc make typical “noise” patterns in the wires??) Using A.I., within a couple of weeks it pretty much figures out which devices in your home are what, and how much electricity each is using, in real time. Via wifi it talks to the company servers and to your app, so you can see what’s going on and review the history.

Here’s an example of its “what’s on now” screen while I was making coffee one day. At that moment our whole house was using 1,008 watts of electricity. At that rate, an hour would be 1,008 watt-hours (duh), aka 1.008 kWh. Beneath the “1,008” it says that’s 28c/hr. (You enter your local price in Settings.)

Below the bubbles is a record of what’s recently turned on and off. I don’t worry about naming everything it spots; I only care about big-ticket energy users.

(In case you’re wondering, I’m not selling this thing and I don’t have an Amazon “affiliate link.” It just came up in a chat on Threads with @ThatAdamGuy Adam Lasnik, in which he mentioned a similar thing he has for detecting water leaks. He hadn’t heard about Sense, so here we are.)

So that’s the “what’s what and what’s going on” part. Now let’s turn to the history.

Hunting it down

I was new to this and at first it didn’t occur to me to poke around in the app to find the problem, but when I opened up the Meter tab, voila: something had clearly gone wrong – a giant spike. You can also see when AC season started, mid-June; you can see the giant spike; and you can see that when it was fixed, the usage immediately dropped back to normal for AC season.

Fixing this required both an electrician and HVAC service. The problem ultimately turned out to be that when our air conditioner was installed ten years earlier, the mom-and-pop installer had (a) used the wrong size circuit breaker(!!!), (b) given us wrong instructions on cleaning the AC, so (c) it’d gotten really dirty inside, so (d) it was jamming every time it tried to kick on, which should have tripped the circuit breaker, but see (a): it was the wrong size breaker(!!!!), so it didn’t trip, so thankfully (e) the AC itself hit its internal shutoff, but then in a few minutes it woke up and tried again. Over and over.

Here’s a zoomed-in view of what was happening: every few minutes it was slamming at 15,000 watts for a moment, then shutting off, then trying again. Yikes. (See what I mean about data??)

I’m giving you a very minimized version of the story – I have a dozen more screen shots of zooming in on the data for more detail, which you’re welcome to see if you really want. :-) But for now this is enough.

Note, in the red graph above, that it’s easy to see when we left town for a week. And, as with all “connected home” systems, we could monitor it while away. Some people think this kind of “Big Brother” monitoring is creepy, and that’s up to them. We like it.

I will add one more thing that I like about Sense, just because it’s a nifty feature. When the A.I. detects a new fingerprint, it notifies you and shows the screen at right, showing the names given to that fingerprint by other users. Indeed, this was our space heater, which warms the bathroom in winter so we don’t have to crank up the furnace for the whole house.

It apparently has lots of other features for managing home solar panels and batteries, but that’s not available where I live (at present).

Knowledge is power.
Data drives it.

The thread from @ThatAdamGuy was about two water leaks detected by his Flume gadget. Without the data, he wouldn’t have known, and aside from the waste, his water bill would have taken a hit.

In my neighborhood we’re not billed individually for water, but of course we are for electricity. For us the Sense system paid for itself in this one incident. I don’t imagine that would be true for most people – most people don’t suffer a 405% “leak” of electricity. But I think we all need to be aware of our energy usage for climate control, and we certainly need to manage our costs.

And to return to my main jam, healthcare, I feel exactly the same about self-management of our health. While I’m no paragon of excellence, I use connected devices to track my weight, my exercise, my glaucoma. As with fixing our AC problem, I still have to do the work of fitness and behavior change – but that can’t even start if I don’t have the information.