Not everyone obsesses about their home energy use. But as rates climb and concern over the impact using electricity from the grid has on climate change, it is becoming increasingly popular to try to get a handle on what you’re using, which devices or appliances are using it, and whether there is anything practical you can do about it. In particular, for anyone thinking of investing in solar, each watt is real dollars, and reducing consumption — at least up to a point — can be a more cost-effective place to start.
That’s where the Sense home energy monitor ($299) comes in. The core of the Sense is a wireless current and voltage meter that installs into your electrical box and reads out how much power you are consuming at any given time. So far, that’s a pretty standard piece of gear. Where the interesting part comes in is that Sense will attempt to figure out the load created by specific appliances, allow you to label them as you figure out what they are, and then provide reports on the consumption from each device and estimated running cost. I’ve had one installed for just over a month, and have lots of findings to report.
Installing the Sense meter
The Sense is actually pretty easy to install. It does need to be wired to a 240-volt breaker, either dedicated or shared. Its sensors are the traditional “clamp” type current meters that can simply be placed around each leg supplying electricity to your house. If your panel has an easily accessible main breaker to shut it off, and you’re comfortable messing with circuit breakers, none of this is super-hard. But if you’re in any doubt, a licensed electrician should be able to do it in 30 minutes or less. Ideally, you’ll mount the Sense inside the electrical box, if there’s room, and run its antenna cable out through one of the punch outs. In our case, there wasn’t room in the box, so we used the provided mounting bracket to attach the Sense to the wall and ran the sensor wires into the box, as you can see from the attached photo.
If you have solar, then you can get an optional ($50) additional pair of current sensors to monitor your solar production. In our case, Sense helped us use one of those to monitor a third electrical leg instead since our house has a separate sub-panel for solar loads. Then you complete setting it up by doing the typical IoT drill of downloading an app, connecting to the meter directly, teaching it about your Wi-Fi, and then setting up an account with Sense that you can access from the app or the web.
Using the Sense App
The Sense mobile and web apps both allow you to look at a chart of your power consumption over time. They also feature graphs of power consumption by device — once Sense has identified a device — and a cute bubble chart of your largest power consumers currently. You can export data, add details for devices Sense has found, and see a list of devices alongside their current consumption.
Sense Is a Slow, but Patient, Learner
Sense learns about devices in your home or office by patiently watching power consumption, and looking for patterns in power usage. It combines your data with its database of devices found by other users to try to guess when it has found an identifiable power load. Once it does, it will attempt to put it in a category like “Light” or “Heat” and ask you if you recognize it and want to label it further.
Because Sense requires a lot of power cycles to identify devices, it can take days, weeks, or even months for it to sort out devices that don’t turn on and off all the time. In fact, it doesn’t have a clue about devices that are always on and lumps them into an “Always On” category. In our case, it found our refrigerator, oven, and microwave within a couple of weeks, although it seems to have lumped our Dishwasher and Instant Pot cooker together into a single appliance for some reason.
Using Sense to Isolate Power Hogs Manually
In our case, since we both run businesses from our house (all the time, not just now), a lot of our power consumption is computers, servers, and networking equipment. I was hopeful that Sense could learn to identify some of that and give us an idea of which ones were power hogs. Unfortunately, even after a month, it couldn’t. However, it did let us do a much more effective job of measuring them manually than we used to. Previously we had to either plug each device in turn into a portable power meter and let it run, or have someone with a radio out at our electric meter watching the change in power consumption when it was turned off and then back on. Now it was easy to stand by the electrical box and watch power consumption on the app as breakers were flipped off and back on (note that first, we made sure sensitive devices were on UPS backups, so they didn’t lose power, they just stopped drawing it from the box). That was helpful, but not entirely fulfilling. Fortunately, the folks at Sense showed me there is a better approach.
Smart Plugs Are Pretty Important
Sense has integrated with a variety of smart plugs and power strips. Once you activate one of those, not only can you see the load in the devices’s app, but the plug is automatically discovered by Sense and added to your device inventory. For a power strip, each plug appears separately. We tried this out with a Kasa Smart Plug Power Strip ($79.97) that provides six measured outlets along with 3 USB charging ports. By placing it in our “machine room” we were able to easily label our NAS devices and network equipment into the Sense app. Eventually, I’ll probably get some single smart plugs for our desktop computers and cable box. You can also control devices that are connected to a smart strip or plug, so if you find some that are power hogs, you can set up schedules for them that way.
Here’s What We Learned That We Didn’t Know Before
We’ve been pretty obsessive about trying to quantify our electricity usage for a while — especially since we spent a lot on a solar installation 20 years ago, and upgraded it again recently, keeping our cost per KWh top of mind. So we already had a good handle on the easy stuff, but we’ve still learned plenty. First, it was a relief to find out that our 30-year-old refrigerator is actually fairly energy efficient, so we could stop worrying about whether we needed to replace it. Second, it was very helpful to start to get a handle on the 24 x 7 load of some of the NAS units that we mostly use to store backups. I realized that by time-shifting when we ran backups and the power schedules of those servers, we could save some power. It also makes clear when one of our servers or desktops isn’t falling asleep as scheduled (a problem I’ve had frequently with Windows), so that we knew to debug the issue. It can even alert you when a particular device powers on or off, although we haven’t really used that feature yet.
Adding a Sense to your home probably won’t change your life, and if you’re not already curious enough about your energy usage to be trying to figure it out on your own, it is unlikely to turn you into an energy sleuth. But if you are curious about where your power goes, and whether there are steps you can take to reduce your electricity demand, then it is a unique and helpful tool.
- Going Solar Part 1: How to Plan a Successful Solar Panel Project
- Going Solar Part 2: Ensuring the Project Is a Success
- PCMag: How to Set Up Your Smart Home: A Beginner’s Guide